diff --git a/.circleci/config.yml b/.circleci/config.yml
index a4671f4f58a64..668de8c1a5a83 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -7,32 +7,6 @@ aliases:
   - &environment
     TZ: /usr/share/zoneinfo/America/Los_Angeles
 
-  - &restore_yarn_cache_fixtures_dom
-    restore_cache:
-      name: Restore yarn cache for fixtures/dom
-      keys:
-        - v2-yarn_cache-{{ arch }}-{{ checksum "yarn.lock" }}-fixtures/dom
-
-  - &yarn_install_fixtures_dom
-    run:
-      name: Install dependencies in fixtures/dom
-      working_directory: fixtures/dom
-      command: yarn install --frozen-lockfile --cache-folder ~/.cache/yarn
-
-  - &yarn_install_fixtures_dom_retry
-    run:
-      name: Install dependencies in fixtures/dom (retry)
-      when: on_fail
-      working_directory: fixtures/dom
-      command: yarn install --frozen-lockfile --cache-folder ~/.cache/yarn
-
-  - &save_yarn_cache_fixtures_dom
-    save_cache:
-      name: Save yarn cache for fixtures/dom
-      key: v2-yarn_cache-{{ arch }}-{{ checksum "yarn.lock" }}-fixtures/dom
-      paths:
-        - ~/.cache/yarn
-
   - &TEST_PARALLELISM 20
 
   - &attach_workspace
@@ -74,518 +48,290 @@ parameters:
     default: ''
 
 jobs:
-  scrape_warning_messages:
-    docker: *docker
-    environment: *environment
-
-    steps:
-      - checkout
-      - setup_node_modules
-      - run:
-          command: |
-            mkdir -p ./build/__test_utils__
-            node ./scripts/print-warnings/print-warnings.js > build/__test_utils__/ReactAllWarnings.js
-      - persist_to_workspace:
-          root: .
-          paths:
-            - build
-
-  yarn_build:
-    docker: *docker
-    environment: *environment
-    parallelism: 40
-    steps:
-      - checkout
-      - setup_node_modules
-      - run: yarn build --ci=circleci
-      - persist_to_workspace:
-          root: .
-          paths:
-            - build
-
-  download_build:
-    docker: *docker
-    environment: *environment
-    parameters:
-      revision:
-        type: string
-    steps:
-      - checkout
-      - setup_node_modules
-      - run:
-          name: Download artifacts for revision
-          command: |
-              git fetch origin main
-              cd ./scripts/release && yarn && cd ../../
-              scripts/release/download-experimental-build.js --commit=<< parameters.revision >> --allowBrokenCI
-      - persist_to_workspace:
-          root: .
-          paths:
-            - build
-
-  download_base_build_for_sizebot:
-    docker: *docker
-    environment: *environment
-    steps:
-      - checkout
-      - setup_node_modules
-      - run:
-          name: Download artifacts for base revision
-          command: |
-            git fetch origin main
-            cd ./scripts/release && yarn && cd ../../
-            scripts/release/download-experimental-build.js --commit=$(git merge-base HEAD origin/main) --allowBrokenCI
-            mv ./build ./base-build
-
-      - run:
-          # TODO: The `download-experimental-build` script copies the npm
-          # packages into the `node_modules` directory. This is a historical
-          # quirk of how the release script works. Let's pretend they
-          # don't exist.
-          name: Delete extraneous files
-          command: rm -rf ./base-build/node_modules
-
-      - persist_to_workspace:
-          root: .
-          paths:
-            - base-build
-
-  process_artifacts_combined:
-    docker: *docker
-    environment: *environment
-    steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      - setup_node_modules
-      - run: echo "<< pipeline.git.revision	>>" >> build/COMMIT_SHA
-        # Compress build directory into a single tarball for easy download
-      - run: tar -zcvf ./build.tgz ./build
-        # TODO: Migrate scripts to use `build` directory instead of `build2`
-      - run: cp ./build.tgz ./build2.tgz
-      - store_artifacts:
-          path: ./build2.tgz
-      - store_artifacts:
-          path: ./build.tgz
-
-  sizebot:
-    docker: *docker
-    environment: *environment
-    steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      - run: echo "<< pipeline.git.revision	>>" >> build/COMMIT_SHA
-      - setup_node_modules
-      - run:
-          command: node ./scripts/tasks/danger
-      - store_artifacts:
-          path: sizebot-message.md
-
-  build_devtools_and_process_artifacts:
-    docker: *docker
-    environment: *environment
-    steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      - setup_node_modules
-      - run:
-          environment:
-            RELEASE_CHANNEL: experimental
-          command: ./scripts/circleci/pack_and_store_devtools_artifacts.sh
-      - store_artifacts:
-          path: ./build/devtools.tgz
-      # Simplifies getting the extension for local testing
-      - store_artifacts:
-          path: ./build/devtools/chrome-extension.zip
-          destination: react-devtools-chrome-extension.zip
-      - store_artifacts:
-          path: ./build/devtools/firefox-extension.zip
-          destination: react-devtools-firefox-extension.zip
-
-  run_devtools_e2e_tests:
-    docker: *docker
-    environment: *environment
-    steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      - setup_node_modules
-      - run:
-          name: Playwright install deps
-          command: |
-            npx playwright install
-            sudo npx playwright install-deps
-      - run:
-          environment:
-            RELEASE_CHANNEL: experimental
-          command: ./scripts/circleci/run_devtools_e2e_tests.js
-
-  run_fixtures_flight_tests:
-    docker: *docker
-    environment: *environment
-    steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      # Fixture copies some built packages from the workroot after install.
-      # That means dependencies of the built packages are not installed.
-      # We need to install dependencies of the workroot to fulfill all dependency constraints
-      - setup_node_modules
-      - restore_cache:
-          name: Restore yarn cache of fixture
-          keys:
-            - v2-yarn_cache_fixtures_flight-{{ arch }}-{{ checksum "yarn.lock" }}
-      - run:
-          name: Install fixture dependencies
-          working_directory: fixtures/flight
-          command: |
-            yarn install --frozen-lockfile --cache-folder ~/.cache/yarn
-            if [ $? -ne 0 ]; then
-              yarn install --frozen-lockfile --cache-folder ~/.cache/yarn
-            fi
-      - save_cache:
-          name: Save yarn cache of fixture
-          key: v2-yarn_cache_fixtures_flight-{{ arch }}-{{ checksum "yarn.lock" }}
-          paths:
-            - ~/.cache/yarn
-      - run:
-          working_directory: fixtures/flight
-          name: Playwright install deps
-          command: |
-            npx playwright install
-            sudo npx playwright install-deps
-      - run:
-          name: Run tests
-          working_directory: fixtures/flight
-          command: yarn test
-          environment:
-          # Otherwise the webserver is a blackbox
-            DEBUG: pw:webserver
-      - store_artifacts:
-          path: fixtures/flight/playwright-report
-      - store_artifacts:
-          path: fixtures/flight/test-results
-
-  run_devtools_tests_for_versions:
-    docker: *docker
-    environment: *environment
-    parallelism: *TEST_PARALLELISM
-    parameters:
-      version:
-        type: string
-    steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      - setup_node_modules
-      - run: ./scripts/circleci/download_devtools_regression_build.js << parameters.version >> --replaceBuild
-      - run: node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion << parameters.version >> --ci=circleci
-
-  run_devtools_e2e_tests_for_versions:
-    docker: *docker
-    environment: *environment
-    parallelism: *TEST_PARALLELISM
-    parameters:
-      version:
-        type: string
+  # yarn_build:
+  #   docker: *docker
+  #   environment: *environment
+  #   parallelism: 40
+  #   steps:
+  #     - checkout
+  #     - setup_node_modules
+  #     - run: yarn build --ci=circleci
+  #     - persist_to_workspace:
+  #         root: .
+  #         paths:
+  #           - build
+
+  # download_build:
+  #   docker: *docker
+  #   environment: *environment
+  #   parameters:
+  #     revision:
+  #       type: string
+  #   steps:
+  #     - checkout
+  #     - setup_node_modules
+  #     - run:
+  #         name: Download artifacts for revision
+  #         command: |
+  #             git fetch origin main
+  #             cd ./scripts/release && yarn && cd ../../
+  #             scripts/release/download-experimental-build.js --commit=<< parameters.revision >> --allowBrokenCI
+  #     - persist_to_workspace:
+  #         root: .
+  #         paths:
+  #           - build
+
+  # process_artifacts_combined:
+  #   docker: *docker
+  #   environment: *environment
+  #   steps:
+  #     - checkout
+  #     - attach_workspace:
+  #         at: .
+  #     - setup_node_modules
+  #     - run: echo "<< pipeline.git.revision	>>" >> build/COMMIT_SHA
+  #     - run: |
+  #         mkdir -p ./build/__test_utils__
+  #         node ./scripts/print-warnings/print-warnings.js > build/__test_utils__/ReactAllWarnings.js
+  #     # Compress build directory into a single tarball for easy download
+  #     - run: tar -zcvf ./build.tgz ./build
+  #       # TODO: Migrate scripts to use `build` directory instead of `build2`
+  #     - run: cp ./build.tgz ./build2.tgz
+  #     - store_artifacts:
+  #         path: ./build2.tgz
+  #     - store_artifacts:
+  #         path: ./build.tgz
+
+  # build_devtools_and_process_artifacts:
+  #   docker: *docker
+  #   environment: *environment
+  #   steps:
+  #     - checkout
+  #     - attach_workspace:
+  #         at: .
+  #     - setup_node_modules
+  #     - run:
+  #         environment:
+  #           RELEASE_CHANNEL: experimental
+  #         command: ./scripts/circleci/pack_and_store_devtools_artifacts.sh
+  #     - store_artifacts:
+  #         path: ./build/devtools.tgz
+  #     # Simplifies getting the extension for local testing
+  #     - store_artifacts:
+  #         path: ./build/devtools/chrome-extension.zip
+  #         destination: react-devtools-chrome-extension.zip
+  #     - store_artifacts:
+  #         path: ./build/devtools/firefox-extension.zip
+  #         destination: react-devtools-firefox-extension.zip
+
+  # run_devtools_e2e_tests:
+  #   docker: *docker
+  #   environment: *environment
+  #   steps:
+  #     - checkout
+  #     - attach_workspace:
+  #         at: .
+  #     - setup_node_modules
+  #     - run:
+  #         name: Playwright install deps
+  #         command: |
+  #           npx playwright install
+  #           sudo npx playwright install-deps
+  #     - run:
+  #         environment:
+  #           RELEASE_CHANNEL: experimental
+  #         command: ./scripts/circleci/run_devtools_e2e_tests.js
+
+  # run_devtools_tests_for_versions:
+  #   docker: *docker
+  #   environment: *environment
+  #   parallelism: *TEST_PARALLELISM
+  #   parameters:
+  #     version:
+  #       type: string
+  #   steps:
+  #     - checkout
+  #     - attach_workspace:
+  #         at: .
+  #     - setup_node_modules
+  #     - run: ./scripts/circleci/download_devtools_regression_build.js << parameters.version >> --replaceBuild
+  #     - run: node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion << parameters.version >> --ci=circleci
+
+  # run_devtools_e2e_tests_for_versions:
+  #   docker: *docker
+  #   environment: *environment
+  #   parallelism: *TEST_PARALLELISM
+  #   parameters:
+  #     version:
+  #       type: string
+  #   steps:
+  #     - checkout
+  #     - attach_workspace:
+  #         at: .
+  #     - setup_node_modules
+  #     - run:
+  #         name: Playwright install deps
+  #         command: |
+  #           npx playwright install
+  #           sudo npx playwright install-deps
+  #     - run: ./scripts/circleci/download_devtools_regression_build.js << parameters.version >>
+  #     - run:
+  #         environment:
+  #           RELEASE_CHANNEL: experimental
+  #         command: ./scripts/circleci/run_devtools_e2e_tests.js << parameters.version >>
+  #     - run:
+  #         name: Cleanup build regression folder
+  #         command: rm -r ./build-regression
+  #     - store_artifacts:
+  #         path: ./tmp/screenshots
+
+  # publish_prerelease:
+  #   parameters:
+  #     commit_sha:
+  #       type: string
+  #     release_channel:
+  #       type: string
+  #     dist_tag:
+  #       type: string
+  #   docker: *docker
+  #   environment: *environment
+  #   steps:
+  #     - checkout
+  #     - setup_node_modules
+  #     - run:
+  #         name: Run publish script
+  #         command: |
+  #           git fetch origin main
+  #           cd ./scripts/release && yarn && cd ../../
+  #           scripts/release/prepare-release-from-ci.js --skipTests -r << parameters.release_channel >> --commit=<< parameters.commit_sha >>
+  #           cp ./scripts/release/ci-npmrc ~/.npmrc
+  #           scripts/release/publish.js --ci --tags << parameters.dist_tag >>
+
+  test_job:
+    docker:
+      - image: cimg/base:stable
+    resource_class: small
     steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      - setup_node_modules
       - run:
-          name: Playwright install deps
+          name: Where am I?
           command: |
-            npx playwright install
-            sudo npx playwright install-deps
-      - run: ./scripts/circleci/download_devtools_regression_build.js << parameters.version >>
-      - run:
-          environment:
-            RELEASE_CHANNEL: experimental
-          command: ./scripts/circleci/run_devtools_e2e_tests.js << parameters.version >>
-      - run:
-          name: Cleanup build regression folder
-          command: rm -r ./build-regression
-      - store_artifacts:
-          path: ./tmp/screenshots
-
-  yarn_lint_build:
-    docker: *docker
-    environment: *environment
-    steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      - setup_node_modules
-      - run: yarn lint-build
-
-  yarn_check_release_dependencies:
-    docker: *docker
-    environment: *environment
-    steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      - setup_node_modules
-      - run: yarn check-release-dependencies
-
-
-  check_error_codes:
-    docker: *docker
-    environment: *environment
-    steps:
-      - checkout
-      - attach_workspace: *attach_workspace
-      - setup_node_modules
-      - run:
-          name: Search build artifacts for unminified errors
-          command: |
-            yarn extract-errors
-            git diff --quiet || (echo "Found unminified errors. Either update the error codes map or disable error minification for the affected build, if appropriate." && false)
-
-  yarn_test_build:
-    docker: *docker
-    environment: *environment
-    parallelism: *TEST_PARALLELISM
-    parameters:
-      args:
-        type: string
-    steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      - setup_node_modules
-      - run: yarn test --build <<parameters.args>> --ci=circleci
-
-  RELEASE_CHANNEL_stable_yarn_test_dom_fixtures:
-    docker: *docker
-    environment: *environment
-    steps:
-      - checkout
-      - attach_workspace:
-          at: .
-      - setup_node_modules
-      - *restore_yarn_cache_fixtures_dom
-      - *yarn_install_fixtures_dom
-      - *yarn_install_fixtures_dom_retry
-      - *save_yarn_cache_fixtures_dom
-      - run:
-          name: Run DOM fixture tests
-          environment:
-            RELEASE_CHANNEL: stable
-          working_directory: fixtures/dom
-          command: |
-            yarn predev
-            yarn test --maxWorkers=2
-
-  publish_prerelease:
-    parameters:
-      commit_sha:
-        type: string
-      release_channel:
-        type: string
-      dist_tag:
-        type: string
-    docker: *docker
-    environment: *environment
-    steps:
-      - checkout
-      - setup_node_modules
-      - run:
-          name: Run publish script
-          command: |
-            git fetch origin main
-            cd ./scripts/release && yarn && cd ../../
-            scripts/release/prepare-release-from-ci.js --skipTests -r << parameters.release_channel >> --commit=<< parameters.commit_sha >>
-            cp ./scripts/release/ci-npmrc ~/.npmrc
-            scripts/release/publish.js --ci --tags << parameters.dist_tag >>
-
+            echo "Running on branch << pipeline.git.branch >> "
+            echo ""
+            echo ""
+            echo "Running on commit << pipeline.git.revision >>"
 workflows:
 
-  build_and_test:
-    unless: << pipeline.parameters.prerelease_commit_sha >>
-    jobs:
-      - yarn_build:
-          filters:
-            branches:
-              ignore:
-                - builds/facebook-www
-      - scrape_warning_messages:
-          filters:
-            branches:
-              ignore:
-                - builds/facebook-www
-      - process_artifacts_combined:
-          requires:
-            - scrape_warning_messages
-            - yarn_build
-      - yarn_test_build:
-          requires:
-            - yarn_build
-          matrix:
-            parameters:
-              args:
-                # Intentionally passing these as strings instead of creating a
-                # separate parameter per CLI argument, since it's easier to
-                # control/see which combinations we want to run.
-                - "-r=stable --env=development"
-                - "-r=stable --env=production"
-                - "-r=experimental --env=development"
-                - "-r=experimental --env=production"
-
-                # Dev Tools
-                - "--project=devtools -r=experimental"
-
-                # TODO: Update test config to support www build tests
-                # - "-r=www-classic --env=development --variant=false"
-                # - "-r=www-classic --env=production --variant=false"
-                # - "-r=www-classic --env=development --variant=true"
-                # - "-r=www-classic --env=production --variant=true"
-                # - "-r=www-modern --env=development --variant=false"
-                # - "-r=www-modern --env=production --variant=false"
-                # - "-r=www-modern --env=development --variant=true"
-                # - "-r=www-modern --env=production --variant=true"
-
-                # TODO: Update test config to support xplat build tests
-                # - "-r=xplat --env=development --variant=false"
-                # - "-r=xplat --env=development --variant=true"
-                # - "-r=xplat --env=production --variant=false"
-                # - "-r=xplat --env=production --variant=true"
-
-                # TODO: Test more persistent configurations?
-      - download_base_build_for_sizebot:
-          filters:
-            branches:
-              ignore:
-                - main
-                - builds/facebook-www
-      - sizebot:
-          filters:
-            branches:
-              ignore:
-                - main
-          requires:
-            - download_base_build_for_sizebot
-            - yarn_build
-      - yarn_lint_build:
-          requires:
-            - yarn_build
-      - yarn_check_release_dependencies:
-          requires:
-            - yarn_build
-      - check_error_codes:
-          requires:
-            - yarn_build
-      - RELEASE_CHANNEL_stable_yarn_test_dom_fixtures:
-          requires:
-            - yarn_build
-      - build_devtools_and_process_artifacts:
-          requires:
-            - yarn_build
-      - run_devtools_e2e_tests:
-          requires:
-            - build_devtools_and_process_artifacts
-      - run_fixtures_flight_tests:
-          requires:
-            - yarn_build
-
-  devtools_regression_tests:
-    unless: << pipeline.parameters.prerelease_commit_sha >>
-    triggers:
-      - schedule:
-          # DevTools regression tests run once a day
-          cron: "0 0 * * *"
-          filters:
-            branches:
-              only:
-                - main
-    jobs:
-      - download_build:
-          revision: << pipeline.git.revision >>
-      - build_devtools_and_process_artifacts:
-          requires:
-            - download_build
-      - run_devtools_tests_for_versions:
-          requires:
-            - build_devtools_and_process_artifacts
-          matrix:
-            parameters:
-              version:
-                - "16.0"
-                - "16.5" # schedule package
-                - "16.8" # hooks
-                - "17.0"
-                - "18.0"
-      - run_devtools_e2e_tests_for_versions:
-          requires:
-            - build_devtools_and_process_artifacts
-          matrix:
-            parameters:
-              version:
-                - "16.0"
-                - "16.5" # schedule package
-                - "16.8" # hooks
-                - "17.0"
-                - "18.0"
-
-  # Used to publish a prerelease manually via the command line
-  publish_preleases:
-    when: << pipeline.parameters.prerelease_commit_sha >>
-    jobs:
-      - publish_prerelease:
-          name: Publish to Canary channel
-          commit_sha: << pipeline.parameters.prerelease_commit_sha >>
-          release_channel: stable
-          # The tags to use when publishing canaries. The main one we should
-          # always include is "canary" but we can use multiple (e.g. alpha,
-          # beta, rc). To declare multiple, use a comma-separated string, like
-          # this:
-          #   dist_tag: "canary,alpha,beta,rc"
-          #
-          # TODO: We currently tag canaries with "next" in addition to "canary"
-          # because this used to be called the "next" channel and some
-          # downstream consumers might still expect that tag. We can remove this
-          # after some time has elapsed and the change has been communicated.
-          dist_tag: "canary,next,rc"
-      - publish_prerelease:
-          name: Publish to Experimental channel
-          requires:
-            # NOTE: Intentionally running these jobs sequentially because npm
-            # will sometimes fail if you try to concurrently publish two
-            # different versions of the same package, even if they use different
-            # dist tags.
-            - Publish to Canary channel
-          commit_sha: << pipeline.parameters.prerelease_commit_sha >>
-          release_channel: experimental
-          dist_tag: experimental
-
-  # Publishes on a cron schedule
-  publish_preleases_nightly:
-    unless: << pipeline.parameters.prerelease_commit_sha >>
-    triggers:
-      - schedule:
-          # At 10 minutes past 16:00 on Mon, Tue, Wed, Thu, and Fri
-          cron: "10 16 * * 1,2,3,4,5"
-          filters:
-            branches:
-              only:
-                - main
+  test_workflow:
     jobs:
-      - publish_prerelease:
-          name: Publish to Canary channel
-          commit_sha: << pipeline.git.revision >>
-          release_channel: stable
-          dist_tag: "canary,next,rc"
-      - publish_prerelease:
-          name: Publish to Experimental channel
-          requires:
-            # NOTE: Intentionally running these jobs sequentially because npm
-            # will sometimes fail if you try to concurrently publish two
-            # different versions of the same package, even if they use different
-            # dist tags.
-            - Publish to Canary channel
-          commit_sha: << pipeline.git.revision >>
-          release_channel: experimental
-          dist_tag: experimental
+      - test_job
+
+  # # build_and_test:
+  # #   unless: << pipeline.parameters.prerelease_commit_sha >>
+  # #   jobs:
+  # #     - yarn_build:
+  # #         filters:
+  # #           branches:
+  # #             ignore:
+  # #               - builds/facebook-www
+  # #     - process_artifacts_combined:
+  # #         requires:
+  # #           - yarn_build
+
+  # devtools_regression_tests:
+  #   unless: << pipeline.parameters.prerelease_commit_sha >>
+  #   triggers:
+  #     - schedule:
+  #         # DevTools regression tests run once a day
+  #         cron: "0 0 * * *"
+  #         filters:
+  #           branches:
+  #             only:
+  #               - main
+  #   jobs:
+  #     - download_build:
+  #         revision: << pipeline.git.revision >>
+  #     - build_devtools_and_process_artifacts:
+  #         requires:
+  #           - download_build
+  #     - run_devtools_tests_for_versions:
+  #         requires:
+  #           - build_devtools_and_process_artifacts
+  #         matrix:
+  #           parameters:
+  #             version:
+  #               - "16.0"
+  #               - "16.5" # schedule package
+  #               - "16.8" # hooks
+  #               - "17.0"
+  #               - "18.0"
+  #     - run_devtools_e2e_tests_for_versions:
+  #         requires:
+  #           - build_devtools_and_process_artifacts
+  #         matrix:
+  #           parameters:
+  #             version:
+  #               - "16.0"
+  #               - "16.5" # schedule package
+  #               - "16.8" # hooks
+  #               - "17.0"
+  #               - "18.0"
+
+  # # Used to publish a prerelease manually via the command line
+  # publish_preleases:
+  #   when: << pipeline.parameters.prerelease_commit_sha >>
+  #   jobs:
+  #     - publish_prerelease:
+  #         name: Publish to Canary channel
+  #         commit_sha: << pipeline.parameters.prerelease_commit_sha >>
+  #         release_channel: stable
+  #         # The tags to use when publishing canaries. The main one we should
+  #         # always include is "canary" but we can use multiple (e.g. alpha,
+  #         # beta, rc). To declare multiple, use a comma-separated string, like
+  #         # this:
+  #         #   dist_tag: "canary,alpha,beta,rc"
+  #         #
+  #         # TODO: We currently tag canaries with "next" in addition to "canary"
+  #         # because this used to be called the "next" channel and some
+  #         # downstream consumers might still expect that tag. We can remove this
+  #         # after some time has elapsed and the change has been communicated.
+  #         dist_tag: "canary,next,rc"
+  #     - publish_prerelease:
+  #         name: Publish to Experimental channel
+  #         requires:
+  #           # NOTE: Intentionally running these jobs sequentially because npm
+  #           # will sometimes fail if you try to concurrently publish two
+  #           # different versions of the same package, even if they use different
+  #           # dist tags.
+  #           - Publish to Canary channel
+  #         commit_sha: << pipeline.parameters.prerelease_commit_sha >>
+  #         release_channel: experimental
+  #         dist_tag: experimental
+
+  # # Publishes on a cron schedule
+  # publish_preleases_nightly:
+  #   unless: << pipeline.parameters.prerelease_commit_sha >>
+  #   triggers:
+  #     - schedule:
+  #         # At 10 minutes past 16:00 on Mon, Tue, Wed, Thu, and Fri
+  #         cron: "10 16 * * 1,2,3,4,5"
+  #         filters:
+  #           branches:
+  #             only:
+  #               - main
+  #   jobs:
+  #     - publish_prerelease:
+  #         name: Publish to Canary channel
+  #         commit_sha: << pipeline.git.revision >>
+  #         release_channel: stable
+  #         dist_tag: "canary,next,rc"
+  #     - publish_prerelease:
+  #         name: Publish to Experimental channel
+  #         requires:
+  #           # NOTE: Intentionally running these jobs sequentially because npm
+  #           # will sometimes fail if you try to concurrently publish two
+  #           # different versions of the same package, even if they use different
+  #           # dist tags.
+  #           - Publish to Canary channel
+  #         commit_sha: << pipeline.git.revision >>
+  #         release_channel: experimental
+  #         dist_tag: experimental
diff --git a/.github/workflows/compiler_playground.yml b/.github/workflows/compiler_playground.yml
index 7f2a75d324d77..eb48a9b210b22 100644
--- a/.github/workflows/compiler_playground.yml
+++ b/.github/workflows/compiler_playground.yml
@@ -5,9 +5,12 @@ on:
     branches: [main]
   pull_request:
     paths:
-      - "compiler/**"
+      - compiler/**
       - .github/workflows/compiler-playground.yml
 
+env:
+  TZ: /usr/share/zoneinfo/America/Los_Angeles
+
 defaults:
   run:
     working-directory: compiler
@@ -20,8 +23,8 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 18.x
-          cache: "yarn"
+          node-version: 18.20.1
+          cache: yarn
           cache-dependency-path: compiler/yarn.lock
       - name: Restore cached node_modules
         uses: actions/cache@v4
diff --git a/.github/workflows/compiler_rust.yml b/.github/workflows/compiler_rust.yml
index cf911b9d476b3..3cda1325ca49e 100644
--- a/.github/workflows/compiler_rust.yml
+++ b/.github/workflows/compiler_rust.yml
@@ -18,6 +18,7 @@ on:
 env:
   CARGO_TERM_COLOR: always
   RUSTFLAGS: -Dwarnings
+  TZ: /usr/share/zoneinfo/America/Los_Angeles
 
 defaults:
   run:
diff --git a/.github/workflows/compiler_typescript.yml b/.github/workflows/compiler_typescript.yml
index 233e963bfad74..8576f66a10057 100644
--- a/.github/workflows/compiler_typescript.yml
+++ b/.github/workflows/compiler_typescript.yml
@@ -5,9 +5,12 @@ on:
     branches: [main]
   pull_request:
     paths:
-      - "compiler/**"
+      - compiler/**
       - .github/workflows/compiler-typescript.yml
 
+env:
+  TZ: /usr/share/zoneinfo/America/Los_Angeles
+
 defaults:
   run:
     working-directory: compiler
@@ -31,8 +34,8 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 18.x
-          cache: "yarn"
+          node-version: 18.20.1
+          cache: yarn
           cache-dependency-path: compiler/yarn.lock
       - name: Restore cached node_modules
         uses: actions/cache@v4
@@ -50,8 +53,8 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 18.x
-          cache: "yarn"
+          node-version: 18.20.1
+          cache: yarn
           cache-dependency-path: compiler/yarn.lock
       - name: Restore cached node_modules
         uses: actions/cache@v4
@@ -74,8 +77,8 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 18.x
-          cache: "yarn"
+          node-version: 18.20.1
+          cache: yarn
           cache-dependency-path: compiler/yarn.lock
       - name: Restore cached node_modules
         uses: actions/cache@v4
diff --git a/.github/workflows/devtools_check_repro.yml b/.github/workflows/devtools_check_repro.yml
index adaef6ac32bd6..735371e3a8f7d 100644
--- a/.github/workflows/devtools_check_repro.yml
+++ b/.github/workflows/devtools_check_repro.yml
@@ -5,6 +5,9 @@ on:
   issue_comment:
     types: [created, edited]
 
+env:
+  TZ: /usr/share/zoneinfo/America/Los_Angeles
+
 jobs:
   check-repro:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/runtime_build_and_test.yml b/.github/workflows/runtime_build_and_test.yml
new file mode 100644
index 0000000000000..2cf5011a0012a
--- /dev/null
+++ b/.github/workflows/runtime_build_and_test.yml
@@ -0,0 +1,609 @@
+name: (Runtime) Build and Test
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    paths-ignore:
+      - compiler/**
+
+env:
+  TZ: /usr/share/zoneinfo/America/Los_Angeles
+
+jobs:
+  # ----- FLOW -----
+  discover_flow_inline_configs:
+    name: Discover flow inline configs
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.result }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/github-script@v7
+        id: set-matrix
+        with:
+          script: |
+            const inlinedHostConfigs = require('./scripts/shared/inlinedHostConfigs.js');
+            return inlinedHostConfigs.map(config => config.shortName);
+
+  flow:
+    name: Flow check ${{ matrix.flow_inline_config_shortname }}
+    needs: discover_flow_inline_configs
+    runs-on: ubuntu-latest
+    continue-on-error: true
+    strategy:
+      matrix:
+        flow_inline_config_shortname: ${{ fromJSON(needs.discover_flow_inline_configs.outputs.matrix) }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - run: node ./scripts/tasks/flow-ci ${{ matrix.flow_inline_config_shortname }}
+
+  # ----- FIZZ -----
+  check_generated_fizz_runtime:
+    name: Confirm generated inline Fizz runtime is up to date
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - run: |
+          yarn generate-inline-fizz-runtime
+          git diff --quiet || (echo "There was a change to the Fizz runtime. Run `yarn generate-inline-fizz-runtime` and check in the result." && false)
+
+  # ----- FEATURE FLAGS -----
+  flags:
+    name: Check flags
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - run: yarn flags
+
+  # ----- TESTS -----
+  test:
+    name: yarn test ${{ matrix.params }} (Shard ${{ matrix.shard }})
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        params:
+          - "-r=stable --env=development"
+          - "-r=stable --env=production"
+          - "-r=experimental --env=development"
+          - "-r=experimental --env=production"
+          - "-r=www-classic --env=development --variant=false"
+          - "-r=www-classic --env=production --variant=false"
+          - "-r=www-classic --env=development --variant=true"
+          - "-r=www-classic --env=production --variant=true"
+          - "-r=www-modern --env=development --variant=false"
+          - "-r=www-modern --env=production --variant=false"
+          - "-r=www-modern --env=development --variant=true"
+          - "-r=www-modern --env=production --variant=true"
+          - "-r=xplat --env=development --variant=false"
+          - "-r=xplat --env=development --variant=true"
+          - "-r=xplat --env=production --variant=false"
+          - "-r=xplat --env=production --variant=true"
+          # TODO: Test more persistent configurations?
+          - "-r=stable --env=development --persistent"
+          - "-r=experimental --env=development --persistent"
+        shard:
+          - 1/5
+          - 2/5
+          - 3/5
+          - 4/5
+          - 5/5
+    continue-on-error: true
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - run: yarn test ${{ matrix.params }} --ci=github --shard=${{ matrix.shard }}
+
+  # ----- BUILD -----
+  build_and_lint:
+    name: yarn build and lint
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        # yml is dumb. update the --total arg to yarn build if you change the number of workers
+        worker_id: [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19]
+        release_channel: [stable, experimental]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 11.0.22
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - run: yarn build --index=${{ matrix.worker_id }} --total=20 --r=${{ matrix.release_channel }} --ci=github
+        env:
+          CI: github
+          RELEASE_CHANNEL: ${{ matrix.release_channel }}
+          NODE_INDEX: ${{ matrix.worker_id }}
+      - name: Lint build
+        run: yarn lint-build
+      - name: Display structure of build
+        run: ls -R build
+      - name: Archive build
+        uses: actions/upload-artifact@v4
+        with:
+          name: _build_${{ matrix.worker_id }}_${{ matrix.release_channel }}
+          path: build
+
+  test_build:
+    name: yarn test-build
+    needs: build_and_lint
+    strategy:
+      matrix:
+        test_params: [
+          # Intentionally passing these as strings instead of creating a
+          # separate parameter per CLI argument, since it's easier to
+          # control/see which combinations we want to run.
+          -r=stable --env=development,
+          -r=stable --env=production,
+          -r=experimental --env=development,
+          -r=experimental --env=production,
+
+          # Dev Tools
+          --project=devtools -r=experimental,
+
+          # TODO: Update test config to support www build tests
+          # - "-r=www-classic --env=development --variant=false"
+          # - "-r=www-classic --env=production --variant=false"
+          # - "-r=www-classic --env=development --variant=true"
+          # - "-r=www-classic --env=production --variant=true"
+          # - "-r=www-modern --env=development --variant=false"
+          # - "-r=www-modern --env=production --variant=false"
+          # - "-r=www-modern --env=development --variant=true"
+          # - "-r=www-modern --env=production --variant=true"
+
+          # TODO: Update test config to support xplat build tests
+          # - "-r=xplat --env=development --variant=false"
+          # - "-r=xplat --env=development --variant=true"
+          # - "-r=xplat --env=production --variant=false"
+          # - "-r=xplat --env=production --variant=true"
+
+          # TODO: Test more persistent configurations?
+        ]
+        shard:
+          - 1/3
+          - 2/3
+          - 3/3
+    continue-on-error: true
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - name: Restore archived build
+        uses: actions/download-artifact@v4
+        with:
+          pattern: _build_*
+          path: build
+          merge-multiple: true
+      - name: Display structure of build
+        run: ls -R build
+      - run: yarn test --build ${{ matrix.test_params }} --shard=${{ matrix.shard }} --ci=github
+
+  process_artifacts_combined:
+    name: Process artifacts combined
+    needs: build_and_lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - name: Restore archived build
+        uses: actions/download-artifact@v4
+        with:
+          pattern: _build_*
+          path: build
+          merge-multiple: true
+      - name: Display structure of build
+        run: ls -R build
+      - run: echo ${{ github.sha }} >> build/COMMIT_SHA
+      - name: Scrape warning messages
+        run: |
+          mkdir -p ./build/__test_utils__
+          node ./scripts/print-warnings/print-warnings.js > build/__test_utils__/ReactAllWarnings.js
+        # Compress build directory into a single tarball for easy download
+      - run: tar -zcvf ./build.tgz ./build
+        # TODO: Migrate scripts to use `build` directory instead of `build2`
+      - run: cp ./build.tgz ./build2.tgz
+      - name: Archive build artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: artifacts_combined
+          path: |
+            ./build.tgz
+            ./build2.tgz
+
+  check_error_codes:
+    name: Search build artifacts for unminified errors
+    needs: build_and_lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - name: Restore archived build
+        uses: actions/download-artifact@v4
+        with:
+          pattern: _build_*
+          path: build
+          merge-multiple: true
+      - name: Display structure of build
+        run: ls -R build
+      - name: Search build artifacts for unminified errors
+        run: |
+          yarn extract-errors
+          git diff --quiet || (echo "Found unminified errors. Either update the error codes map or disable error minification for the affected build, if appropriate." && false)
+
+  check_release_dependencies:
+    name: Check release dependencies
+    needs: build_and_lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - name: Restore archived build
+        uses: actions/download-artifact@v4
+        with:
+          pattern: _build_*
+          path: build
+          merge-multiple: true
+      - name: Display structure of build
+        run: ls -R build
+      - run: yarn check-release-dependencies
+
+  RELEASE_CHANNEL_stable_yarn_test_dom_fixtures:
+    name: Check fixtures DOM (stable)
+    needs: build_and_lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: v2-yarn_cache_fixtures_dom-${{ runner.arch }}-${{ runner.os }}-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - run: yarn install --frozen-lockfile --cache-folder ~/.cache/yarn
+        working-directory: fixtures/dom
+      - name: Restore archived build
+        uses: actions/download-artifact@v4
+        with:
+          pattern: _build_*
+          path: build
+          merge-multiple: true
+      - name: Display structure of build
+        run: ls -R build
+      - name: Run DOM fixture tests
+        run: |
+          yarn predev
+          yarn test
+        working-directory: fixtures/dom
+        env:
+          RELEASE_CHANNEL: stable
+
+  # ----- FLIGHT -----
+  run_fixtures_flight_tests:
+    name: Run fixtures Flight tests
+    needs: build_and_lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      # Fixture copies some built packages from the workroot after install.
+      # That means dependencies of the built packages are not installed.
+      # We need to install dependencies of the workroot to fulfill all dependency constraints
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: v2-yarn_cache_fixtures_flight-${{ runner.arch }}-${{ runner.os }}-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - name: Restore archived build
+        uses: actions/download-artifact@v4
+        with:
+          pattern: _build_*
+          path: build
+          merge-multiple: true
+      - name: Display structure of build
+        run: ls -R build
+      - name: Install fixture dependencies
+        working-directory: fixtures/flight
+        run: |
+          yarn install --frozen-lockfile --cache-folder ~/.cache/yarn
+          if [ $? -ne 0 ]; then
+            yarn install --frozen-lockfile --cache-folder ~/.cache/yarn
+          fi
+      - name: Playwright install deps
+        working-directory: fixtures/flight
+        run: |
+          npx playwright install
+          sudo npx playwright install-deps
+      - name: Run tests
+        working-directory: fixtures/flight
+        run: yarn test
+        env:
+          # Otherwise the webserver is a blackbox
+          DEBUG: pw:webserver
+      - name: Archive Flight fixture artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: flight-playwright-report
+          path: fixtures/flight/playwright-report
+      - name: Archive Flight fixture artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: flight-test-results
+          path: fixtures/flight/test-results
+
+  # ----- DEVTOOLS -----
+  build_devtools_and_process_artifacts:
+    name: Build DevTools and process artifacts
+    needs: build_and_lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - name: Restore archived build
+        uses: actions/download-artifact@v4
+        with:
+          pattern: _build_*
+          path: build
+          merge-multiple: true
+      - run: ./scripts/circleci/pack_and_store_devtools_artifacts.sh
+        env:
+          RELEASE_CHANNEL: experimental
+      - name: Display structure of build
+        run: ls -R build
+      - name: Archive devtools build
+        uses: actions/upload-artifact@v4
+        with:
+          name: react-devtools
+          path: build/devtools.tgz
+      # Simplifies getting the extension for local testing
+      - name: Archive chrome extension
+        uses: actions/upload-artifact@v4
+        with:
+          name: react-devtools-chrome-extension
+          path: build/devtools/chrome-extension.zip
+      - name: Archive firefox extension
+        uses: actions/upload-artifact@v4
+        with:
+          name: react-devtools-firefox-extension
+          path: build/devtools/firefox-extension.zip
+
+  run_devtools_e2e_tests:
+    name: Run DevTools e2e tests
+    needs: build_devtools_and_process_artifacts
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - name: Restore archived build
+        uses: actions/download-artifact@v4
+        with:
+          pattern: _build_*
+          path: build
+          merge-multiple: true
+      - run: |
+          npx playwright install
+          sudo npx playwright install-deps
+      - run: ./scripts/circleci/run_devtools_e2e_tests.js
+        env:
+          RELEASE_CHANNEL: experimental
+
+  # ----- SIZEBOT -----
+  download_base_build_for_sizebot:
+    if: ${{ github.event_name == 'pull_request' && github.ref_name != 'main' }}
+    name: Download base build for sizebot
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock', 'scripts/release/yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - run: yarn install --frozen-lockfile
+        working-directory: scripts/release
+      - name: Download artifacts for base revision
+        run: |
+          git fetch origin main
+          GH_TOKEN=${{ github.token }} scripts/release/download-experimental-build-ghaction.js --commit=$(git rev-parse origin/main)
+          mv ./build ./base-build
+      # TODO: The `download-experimental-build` script copies the npm
+      # packages into the `node_modules` directory. This is a historical
+      # quirk of how the release script works. Let's pretend they
+      # don't exist.
+      - name: Delete extraneous files
+        run: rm -rf ./base-build/node_modules
+      - name: Display structure of base-build
+        run: ls -R base-build
+      - name: Archive base-build
+        uses: actions/upload-artifact@v4
+        with:
+          name: base-build
+          path: base-build
+
+  sizebot:
+    name: Run sizebot
+    needs: [build_and_lint, download_base_build_for_sizebot]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18.20.1
+          cache: yarn
+          cache-dependency-path: yarn.lock
+      - name: Restore cached node_modules
+        uses: actions/cache@v4
+        id: node_modules
+        with:
+          path: "**/node_modules"
+          key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
+      - run: yarn install --frozen-lockfile
+      - name: Restore archived build for PR
+        uses: actions/download-artifact@v4
+        with:
+          pattern: _build_*
+          path: build
+          merge-multiple: true
+      - name: Scrape warning messages
+        run: |
+          mkdir -p ./build/__test_utils__
+          node ./scripts/print-warnings/print-warnings.js > build/__test_utils__/ReactAllWarnings.js
+      - name: Display structure of build for PR
+        run: ls -R build
+      - name: Restore archived base-build from origin/main
+        uses: actions/download-artifact@v4
+        with:
+          name: base-build
+          path: base-build
+      - name: Display structure of base-build from origin/main
+        run: ls -R base-build
+      - run: echo ${{ github.sha }} >> build/COMMIT_SHA
+      - run: node ./scripts/tasks/danger
+      - name: Archive sizebot results
+        uses: actions/upload-artifact@v4
+        with:
+          name: sizebot-message
+          path: sizebot-message.md
diff --git a/.github/workflows/runtime_commit_artifacts.yml b/.github/workflows/runtime_commit_artifacts.yml
index 2c32281634c7c..c665f9b1bd40e 100644
--- a/.github/workflows/runtime_commit_artifacts.yml
+++ b/.github/workflows/runtime_commit_artifacts.yml
@@ -4,6 +4,9 @@ on:
   push:
     branches: [main, meta-www, meta-fbsource]
 
+env:
+  TZ: /usr/share/zoneinfo/America/Los_Angeles
+
 jobs:
   download_artifacts:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/runtime_fuzz_tests.yml b/.github/workflows/runtime_fuzz_tests.yml
index 5b31d115dcd23..dac4dd095a8d4 100644
--- a/.github/workflows/runtime_fuzz_tests.yml
+++ b/.github/workflows/runtime_fuzz_tests.yml
@@ -9,6 +9,10 @@ on:
     inputs:
       prerelease_commit_sha:
         required: false
+
+env:
+  TZ: /usr/share/zoneinfo/America/Los_Angeles
+
 jobs:
   test_fuzz:
     if: inputs.prerelease_commit_sha == ''
diff --git a/.github/workflows/shared_lint.yml b/.github/workflows/shared_lint.yml
index ca851ff2324bf..e06637b168bf9 100644
--- a/.github/workflows/shared_lint.yml
+++ b/.github/workflows/shared_lint.yml
@@ -5,6 +5,9 @@ on:
     branches: [main]
   pull_request:
 
+env:
+  TZ: /usr/share/zoneinfo/America/Los_Angeles
+
 jobs:
   prettier:
     name: Run prettier
@@ -13,8 +16,8 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 18.x
-          cache: "yarn"
+          node-version: 18.20.1
+          cache: yarn
           cache-dependency-path: yarn.lock
       - name: Restore cached node_modules
         uses: actions/cache@v4
@@ -31,8 +34,8 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 18.x
-          cache: "yarn"
+          node-version: 18.20.1
+          cache: yarn
           cache-dependency-path: yarn.lock
       - name: Restore cached node_modules
         uses: actions/cache@v4
@@ -49,8 +52,8 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 18.x
-          cache: "yarn"
+          node-version: 18.20.1
+          cache: yarn
           cache-dependency-path: yarn.lock
       - name: Restore cached node_modules
         uses: actions/cache@v4
@@ -67,8 +70,8 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 18.x
-          cache: "yarn"
+          node-version: 18.20.1
+          cache: yarn
           cache-dependency-path: yarn.lock
       - name: Restore cached node_modules
         uses: actions/cache@v4
diff --git a/.github/workflows/shared_stale.yml b/.github/workflows/shared_stale.yml
index df9854c270a28..9135b9afcaaeb 100644
--- a/.github/workflows/shared_stale.yml
+++ b/.github/workflows/shared_stale.yml
@@ -5,6 +5,9 @@ on:
     # Run hourly
     - cron: '0 * * * *'
 
+env:
+  TZ: /usr/share/zoneinfo/America/Los_Angeles
+
 jobs:
   stale:
     runs-on: ubuntu-latest