diff --git a/build/bin/sage-bootstrap-python b/build/bin/sage-bootstrap-python
deleted file mode 100755
index d51ae4a751b..00000000000
--- a/build/bin/sage-bootstrap-python
+++ /dev/null
@@ -1,78 +0,0 @@
-#!/bin/sh
-
-# Run the system python.
-#
-# This is only for use by the build toolchain.
-#
-# (It has nothing to do with the python3 that configure --with-system-python3
-# is looking for in build/pkgs/python3/spkg-configure.m4.)
-
-if [ -z "$SAGE_ORIG_PATH" ]; then
-    # If not we're running from within sage-env just set the existing path
-    SAGE_ORIG_PATH="$PATH"
-fi
-IFS=':'
-NEW_PATH=""
-for path in $SAGE_ORIG_PATH
-do
-    case "$path" in
-        */.pyenv/shims*);;
-        *) NEW_PATH="$NEW_PATH$path:";;
-    esac
-done
-unset IFS
-SAGE_ORIG_PATH=${NEW_PATH%%':'}
-# In particular, it is invoked by "bootstrap -d" for sage-download-file,
-# i.e., before a configure run, and by "sage-spkg", also for sage-download-file.
-# So it needs to find a python that has the urllib module.
-# For example, on Debian buster, the python3-minimal package does NOT provide it.
-#
-# Also, Issue #20023 removed the vendored argparse library from sage_bootstrap,
-# so we test that python is new enough (>= 2.7) to run it.
-#
-# See https://github.com/sagemath/sage/issues/29090
-
-# Issue #29890: Our first choice is "python", not "python3". This is to avoid
-# a defect of sage_bootstrap on macOS regarding SSL URLs.
-
-# Issue #30177: Also check for hashlib.sha1 to guard against broken python2
-# from old homebrew installations.  Also check whether the current directory
-# is accessible by this python; this is to guard on WSL against Pythons
-# installed somewhere else in Windows.
-
-# Issue #29285: Do not accept pythons that manipulate PATH, such as
-# the shims provided by pyenv.
-
-# Issue #30008: Make it work even if the environment tries to sabotage UTF-8
-# operation in Python 3.0.x-3.6.x by setting LC_ALL=C or similar.
-
-if [ "$LC_ALL" = "C" -o "$LANG" = "C" -o "$LC_CTYPE" = "C" ]; then
-    LC_ALL=$(locale -a | grep -E -i '^(c|en_us)[-.]utf-?8$' | head -n 1)
-    LANG=$LC_ALL
-    export LC_ALL
-    export LANG
-fi
-
-PYTHONS="python python3 python3.12 python3.11 python3.10 python3.9 python3.8 python3.7 python2.7 python3.6 python2"
-# Issue #32405: Prefer a Python that provides ssl with SNI, which allows developers
-# to download from upstream URLs (configure --enable-download-from-upstream-url),
-# in particular from PyPI, which requires SNI.
-for PY in $PYTHONS; do
-    PYTHON="$(PATH="$SAGE_ORIG_PATH" command -v $PY)"
-    if [ -n "$PYTHON" ]; then
-        if CHECK_PATH="$PATH" "$PYTHON" -c "import argparse; import urllib; from hashlib import sha1; from ssl import HAS_SNI; assert HAS_SNI; from os import listdir, environ; listdir(\"$(pwd)\"); assert environ[\"PATH\"] == environ[\"CHECK_PATH\"];" 2>/dev/null; then
-            exec "$PYTHON" "$@"
-        fi
-    fi
-done
-# Second round, no ssl/SNI test.
-for PY in $PYTHONS; do
-    PYTHON="$(PATH="$SAGE_ORIG_PATH" command -v $PY)"
-    if [ -n "$PYTHON" ]; then
-        if CHECK_PATH="$PATH" "$PYTHON" -c "import argparse; import urllib; from hashlib import sha1; from os import listdir, environ; listdir(\"$(pwd)\"); assert environ[\"PATH\"] == environ[\"CHECK_PATH\"];" 2>/dev/null; then
-            exec "$PYTHON" "$@"
-        fi
-    fi
-done
-echo >&2 "$0: error: none of $PYTHONS is a suitable Python"
-exit 1
diff --git a/build/bin/sage-build-num-threads b/build/bin/sage-build-num-threads
index 1ba165b1a21..f8b2bae7c82 100755
--- a/build/bin/sage-build-num-threads
+++ b/build/bin/sage-build-num-threads
@@ -1,4 +1,4 @@
-#!/usr/bin/env sage-bootstrap-python
+#!/usr/bin/env python3
 #
 # Determine the number of threads to be used by Sage.
 #
diff --git a/build/bin/sage-download-file b/build/bin/sage-download-file
index 3a369d29274..5d0e21ec9b9 100755
--- a/build/bin/sage-download-file
+++ b/build/bin/sage-download-file
@@ -1,4 +1,4 @@
-#!/usr/bin/env sage-bootstrap-python
+#!/usr/bin/env python3
 
 # USAGE:
 #
diff --git a/build/bin/sage-flock b/build/bin/sage-flock
index 9611cfde80b..18331e8f0b0 100755
--- a/build/bin/sage-flock
+++ b/build/bin/sage-flock
@@ -1,4 +1,4 @@
-#!/usr/bin/env sage-bootstrap-python
+#!/usr/bin/env python3
 # vim: set filetype=python:
 
 # USAGE:
diff --git a/build/bin/sage-print-system-package-command b/build/bin/sage-print-system-package-command
index 13bafa22dc0..47ca1d5a168 100755
--- a/build/bin/sage-print-system-package-command
+++ b/build/bin/sage-print-system-package-command
@@ -97,7 +97,7 @@ function print_shell_command()
     if [ -z "$WRAP" -o $# -lt 6 ]; then
         echo "${PROMPT}${quoted}"
     else
-        sage-bootstrap-python -c "import textwrap; print(' \\\\\n'.join(textwrap.wrap(r'''${quoted}''', $WRAP, initial_indent=r'''${PROMPT}''', subsequent_indent=r'''${CONTINUATION}''', break_long_words=False, break_on_hyphens=False)))"
+        python3 -c "import textwrap; print(' \\\\\n'.join(textwrap.wrap(r'''${quoted}''', $WRAP, initial_indent=r'''${PROMPT}''', subsequent_indent=r'''${CONTINUATION}''', break_long_words=False, break_on_hyphens=False)))"
     fi
     if [ -n "$OUTPUT_RST" ]; then
         echo
diff --git a/build/bin/sage-spkg-installcheck b/build/bin/sage-spkg-installcheck
index a8ef89ba2aa..7f1b697903e 100755
--- a/build/bin/sage-spkg-installcheck
+++ b/build/bin/sage-spkg-installcheck
@@ -1,4 +1,4 @@
-#!/usr/bin/env sage-bootstrap-python
+#!/usr/bin/env python3
 
 # usage: sage-spkg-installcheck [-h] PKG [SAGE_LOCAL]
 #
diff --git a/build/bin/sage-spkg-uninstall b/build/bin/sage-spkg-uninstall
index e99a914d6af..af13b527f7e 100755
--- a/build/bin/sage-spkg-uninstall
+++ b/build/bin/sage-spkg-uninstall
@@ -1,4 +1,4 @@
-#!/usr/bin/env sage-bootstrap-python
+#!/usr/bin/env python3
 
 # usage: sage-spkg-uninstall [-h] PKG [SAGE_LOCAL]
 #
diff --git a/build/bin/sage-uncompress-spkg b/build/bin/sage-uncompress-spkg
index 98f2c7645d1..c30c9dd4fcf 100755
--- a/build/bin/sage-uncompress-spkg
+++ b/build/bin/sage-uncompress-spkg
@@ -1,4 +1,4 @@
-#!/usr/bin/env sage-bootstrap-python
+#!/usr/bin/env python3
 
 # usage: sage-uncompress-spkg [-h] [-d DIR] PKG [FILE]
 #
diff --git a/build/make/Makefile.in b/build/make/Makefile.in
index b26ef0f9c05..3373e6b3d17 100644
--- a/build/make/Makefile.in
+++ b/build/make/Makefile.in
@@ -33,7 +33,6 @@ SPKG_INST_RELDIR = var/lib/sage/installed
 
 # Aliases for mutually exclusive standard packages selected at configure time
 TOOLCHAIN = @SAGE_TOOLCHAIN@
-PYTHON = python3
 MP_LIBRARY = gmp
 BLAS = openblas
 
@@ -221,12 +220,7 @@ ifneq ($(PYTHON_FOR_VENV),)
 # 3 only).  $(PYTHON) is set in Makefile to python3_venv.
 # Thus $(inst_python3_venv) will an (order-only) dependency of every Python package.
 #
-# TODO: If we reconfigure to build our own Python after having used the system
-# Python, files installed to create the virtualenv should be *removed*.  That
-# could either be done here by the makefile, or in an spkg-preinst for python3
-ifeq ($(PYTHON),python3)
 PYTHON = python3_venv
-endif
 inst_python3_venv = $(SAGE_VENV)/$(SPKG_INST_RELDIR)/python3_venv-3.$(PYTHON_MINOR)-$(subst /,-,$(PYTHON_FOR_VENV))$(findstring --system-site-packages,$(SAGE_VENV_FLAGS))
 
 $(SAGE_VENV)/$(SPKG_INST_RELDIR):
@@ -313,9 +307,8 @@ all-toolchain: base-toolchain
 PYTHON_TOOLCHAIN = setuptools pip setuptools_scm wheel flit_core hatchling python_build meson_python
 
 # Issue #32056: Avoid installed setuptools leaking into the build of python3 by uninstalling it.
-# It will have to be reinstalled anyway because of its dependency on $(PYTHON).
-python3-SAGE_LOCAL-no-deps: setuptools-clean
-python3-SAGE_VENV-no-deps: setuptools-clean
+# python3-SAGE_LOCAL-no-deps: setuptools-clean
+# python3-SAGE_VENV-no-deps: setuptools-clean
 
 # Everything needed to start up Sage using "./sage".  Of course, not
 # every part of Sage will work.  It does not include Maxima for example.
diff --git a/build/pkgs/appnope/spkg-install.in b/build/pkgs/appnope/spkg-install.in
index 6a9ec337a12..01c5cd85806 100644
--- a/build/pkgs/appnope/spkg-install.in
+++ b/build/pkgs/appnope/spkg-install.in
@@ -1,7 +1,7 @@
 cd src
 
 # Only install this package on OS X
-if sage-bootstrap-python -c 'from sys import *; exit(0 if platform == "darwin" else 1)'; then
+if python3 -c 'from sys import *; exit(0 if platform == "darwin" else 1)'; then
     sdh_pip_install .
 else
     echo "Not OS X, skipping installation of package 'appnope'"
diff --git a/build/pkgs/database_stein_watkins_mini/spkg-install.in b/build/pkgs/database_stein_watkins_mini/spkg-install.in
deleted file mode 120000
index d7005d17fc4..00000000000
--- a/build/pkgs/database_stein_watkins_mini/spkg-install.in
+++ /dev/null
@@ -1 +0,0 @@
-../database_stein_watkins/spkg-install.in
\ No newline at end of file
diff --git a/build/pkgs/database_stein_watkins_mini/spkg-install.in b/build/pkgs/database_stein_watkins_mini/spkg-install.in
new file mode 100644
index 00000000000..da13b1e19cc
--- /dev/null
+++ b/build/pkgs/database_stein_watkins_mini/spkg-install.in
@@ -0,0 +1,16 @@
+# spkg-install file for
+# * database_stein_watkins
+# * database_stein_watkins_mini
+
+if [ -z "$SAGE_SHARE" ]; then
+    echo >&2 "SAGE_SHARE undefined ... exiting"
+    echo >&2 "Maybe run 'sage --sh'?"
+    exit 1
+fi
+
+TARGET="${SAGE_SHARE}/stein_watkins"
+if [ ! -d "${TARGET}" ]; then
+   mkdir "${TARGET}"
+fi
+
+exec cp -R src/swdb/* "${TARGET}/"
diff --git a/build/pkgs/openblas/spkg-install.in b/build/pkgs/openblas/spkg-install.in
index dbfcb6c1a75..a3e33c10195 100644
--- a/build/pkgs/openblas/spkg-install.in
+++ b/build/pkgs/openblas/spkg-install.in
@@ -3,7 +3,7 @@ cd src
 # OpenBLAS does not build on 32bit Haswell. Upstream suggests to pass BINARY=32 to default to NEHALEM kernels
 # See https://github.com/xianyi/OpenBLAS/issues/657
 # Right now this affect all 32bit CPUs.
-if [ `sage-bootstrap-python -c "from __future__ import print_function; import platform; print(platform.architecture()[0])"` = "32bit" ]; then
+if [ `python3 -c "from __future__ import print_function; import platform; print(platform.architecture()[0])"` = "32bit" ]; then
     echo >&2 "Building a 32bit version of OpenBLAS."
     OPENBLAS_CONFIGURE="$OPENBLAS_CONFIGURE BINARY=32"
 fi
diff --git a/build/pkgs/openblas/write_pc_file.py b/build/pkgs/openblas/write_pc_file.py
index dc5ebff6de3..0c2a16071f3 100755
--- a/build/pkgs/openblas/write_pc_file.py
+++ b/build/pkgs/openblas/write_pc_file.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env sage-bootstrap-python
+#!/usr/bin/env python3
 
 
 TEMPLATE = """
diff --git a/build/pkgs/sage_docbuild/spkg-install.in b/build/pkgs/sage_docbuild/spkg-install.in
deleted file mode 120000
index 428e161a850..00000000000
--- a/build/pkgs/sage_docbuild/spkg-install.in
+++ /dev/null
@@ -1 +0,0 @@
-../sage_setup/spkg-install.in
\ No newline at end of file
diff --git a/build/pkgs/sage_docbuild/spkg-install.in b/build/pkgs/sage_docbuild/spkg-install.in
new file mode 100644
index 00000000000..da7d7a2870f
--- /dev/null
+++ b/build/pkgs/sage_docbuild/spkg-install.in
@@ -0,0 +1,9 @@
+cd src
+if [ "$SAGE_EDITABLE" = yes ]; then
+    sdh_pip_editable_install .
+    if [ "$SAGE_WHEELS" = yes ]; then
+        sdh_build_and_store_wheel --no-isolation .
+    fi
+else
+    sdh_pip_install .
+fi
diff --git a/build/pkgs/sagemath_categories/spkg-install.in b/build/pkgs/sagemath_categories/spkg-install.in
deleted file mode 120000
index d83cc631c9a..00000000000
--- a/build/pkgs/sagemath_categories/spkg-install.in
+++ /dev/null
@@ -1 +0,0 @@
-../sagemath_objects/spkg-install.in
\ No newline at end of file
diff --git a/build/pkgs/sagemath_categories/spkg-install.in b/build/pkgs/sagemath_categories/spkg-install.in
new file mode 100644
index 00000000000..53c094fde04
--- /dev/null
+++ b/build/pkgs/sagemath_categories/spkg-install.in
@@ -0,0 +1,10 @@
+cd src
+
+export PIP_NO_INDEX=true
+export PIP_FIND_LINKS="file://$SAGE_SPKG_WHEELS"
+
+# First build the sdist, then build the wheel from the sdist.
+# https://pypa-build.readthedocs.io/en/latest/#python--m-build
+# (Important because sagemath-objects uses MANIFEST.in for filtering.)
+# Do not install the wheel.
+sdh_build_and_store_wheel --sdist-then-wheel .
diff --git a/build/pkgs/sagemath_environment/spkg-install.in b/build/pkgs/sagemath_environment/spkg-install.in
deleted file mode 120000
index d83cc631c9a..00000000000
--- a/build/pkgs/sagemath_environment/spkg-install.in
+++ /dev/null
@@ -1 +0,0 @@
-../sagemath_objects/spkg-install.in
\ No newline at end of file
diff --git a/build/pkgs/sagemath_environment/spkg-install.in b/build/pkgs/sagemath_environment/spkg-install.in
new file mode 100644
index 00000000000..53c094fde04
--- /dev/null
+++ b/build/pkgs/sagemath_environment/spkg-install.in
@@ -0,0 +1,10 @@
+cd src
+
+export PIP_NO_INDEX=true
+export PIP_FIND_LINKS="file://$SAGE_SPKG_WHEELS"
+
+# First build the sdist, then build the wheel from the sdist.
+# https://pypa-build.readthedocs.io/en/latest/#python--m-build
+# (Important because sagemath-objects uses MANIFEST.in for filtering.)
+# Do not install the wheel.
+sdh_build_and_store_wheel --sdist-then-wheel .
diff --git a/build/pkgs/sagemath_repl/spkg-install.in b/build/pkgs/sagemath_repl/spkg-install.in
deleted file mode 120000
index d83cc631c9a..00000000000
--- a/build/pkgs/sagemath_repl/spkg-install.in
+++ /dev/null
@@ -1 +0,0 @@
-../sagemath_objects/spkg-install.in
\ No newline at end of file
diff --git a/build/pkgs/sagemath_repl/spkg-install.in b/build/pkgs/sagemath_repl/spkg-install.in
new file mode 100644
index 00000000000..53c094fde04
--- /dev/null
+++ b/build/pkgs/sagemath_repl/spkg-install.in
@@ -0,0 +1,10 @@
+cd src
+
+export PIP_NO_INDEX=true
+export PIP_FIND_LINKS="file://$SAGE_SPKG_WHEELS"
+
+# First build the sdist, then build the wheel from the sdist.
+# https://pypa-build.readthedocs.io/en/latest/#python--m-build
+# (Important because sagemath-objects uses MANIFEST.in for filtering.)
+# Do not install the wheel.
+sdh_build_and_store_wheel --sdist-then-wheel .
diff --git a/build/sage_bootstrap/creator.py b/build/sage_bootstrap/creator.py
index e16002f12f9..f083e75f3cd 100644
--- a/build/sage_bootstrap/creator.py
+++ b/build/sage_bootstrap/creator.py
@@ -127,9 +127,9 @@ def set_python_data_and_scripts(self, pypi_package_name=None, source='normal', d
             else:
                 dependencies = ''
             if source == 'wheel':
-                dependencies_order_only = 'pip $(PYTHON)'
+                dependencies_order_only = 'pip'
             else:
-                dependencies_order_only = '$(PYTHON_TOOLCHAIN) $(PYTHON)'
+                dependencies_order_only = '$(PYTHON_TOOLCHAIN)'
             f.write(dependencies + ' | ' + dependencies_order_only + '\n\n')
             f.write('----------\nAll lines of this file are ignored except the first.\n')
         if source == 'normal':
diff --git a/build/sage_bootstrap/expand_class.py b/build/sage_bootstrap/expand_class.py
index c5bab8a313e..565e23d77ea 100644
--- a/build/sage_bootstrap/expand_class.py
+++ b/build/sage_bootstrap/expand_class.py
@@ -77,7 +77,7 @@ def include_recursive_dependencies(names, package_name):
                 pkg = Package(package_name)
             except FileNotFoundError:
                 # Silently ignore unknown packages,
-                # substitutions such as $(BLAS) $(PYTHON),
+                # substitutions such as $(BLAS)
                 # and optional dependencies of the form $(find-string ...).
                 return
             names.add(package_name)
diff --git a/build/sage_bootstrap/flock.py b/build/sage_bootstrap/flock.py
index bc95a0ecf8f..872fb7d617f 100644
--- a/build/sage_bootstrap/flock.py
+++ b/build/sage_bootstrap/flock.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env sage-bootstrap-python
+#!/usr/bin/env python3
 # vim: set filetype=python:
 """
 This script runs the given command under a file lock (similar to the flock
diff --git a/build/setup.py b/build/setup.py
index b05dcc386ca..16f4ccda4a3 100755
--- a/build/setup.py
+++ b/build/setup.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env sage-bootstrap-python
+#!/usr/bin/env python3
 
 from distutils.core import setup
 
@@ -12,7 +12,7 @@
         'sage_bootstrap.download',
         'sage_bootstrap.compat'
     ],
-    scripts=['bin/sage-package', 'bin/sage-download-file', 'bin/sage-bootstrap-python'],
+    scripts=['bin/sage-package', 'bin/sage-download-file'],
     version='1.0',
     url='https://www.sagemath.org',
 )
diff --git a/build/test/runnable.py b/build/test/runnable.py
index 75edc551fd6..6424725f60d 100755
--- a/build/test/runnable.py
+++ b/build/test/runnable.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env sage-bootstrap-python
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 """
 Utility to test running with different values for ``SAGE_BOOTSTRAP``
diff --git a/configure.ac b/configure.ac
index da23266e19b..cad84f85348 100644
--- a/configure.ac
+++ b/configure.ac
@@ -353,14 +353,6 @@ SAGE_DARWIN_PKG_CONFIG_PATH=
     AC_CHECK_HEADER([zlib.h], [],
        [AC_MSG_ERROR([cannot find libz headers. $SAGE_PREREQ_URL])])
 
-# Check for system python (bootstrap python for build scripts)
-AC_MSG_CHECKING([for Python])
-if SAGE_BOOTSTRAP_PYTHON=$(build/bin/sage-bootstrap-python -c "import sys; print(sys.executable)"); then
-    AC_MSG_RESULT([$SAGE_BOOTSTRAP_PYTHON])
-else
-    AC_MSG_ERROR([You do not have a suitable version of Python installed])
-fi
-
 # check for liblzma
 
 PKG_CHECK_MODULES([liblzma], [liblzma], [], [
@@ -381,7 +373,7 @@ AS_IF([test x"$with_python" = x3], [
     AC_MSG_NOTICE([The meaning of the option --with-python has changed in Sage 9.2. Ignoring.])
     with_python=''
 ])
-AS_IFbuild/bin/sage-bootstrap-python([test x"$with_python" = x"no"],
+AS_IF([test x"$with_python" = x"no"],
       [AC_MSG_ERROR([building Sage --without-python is not supported])])
 
 ac_path_PYTHON3="$with_python"
diff --git a/src/doc/en/developer/packaging.rst b/src/doc/en/developer/packaging.rst
index 0ef010050a9..3d93fd8c657 100644
--- a/src/doc/en/developer/packaging.rst
+++ b/src/doc/en/developer/packaging.rst
@@ -325,28 +325,12 @@ Likewise for :envvar:`CXXFLAGS`, :envvar:`FCFLAGS`, and :envvar:`F77FLAGS`.
     code should go in a separate file (e.g. ``spkg-install.py``), and can
     then be executed from the real ``spkg-install.in`` like:
 
-    .. code-block:: text
-
-        exec sage-bootstrap-python spkg-install.py
-
-    or
-
     .. code-block:: text
 
         exec python3 spkg-install.py
 
-    In more detail: ``sage-bootstrap-python`` runs a version of Python
-    pre-installed on the machine, which is a build prerequisite of Sage.
-    Note that ``sage-bootstrap-python`` accepts a wide range of Python
-    versions, Python >= 2.6 and >= 3.4, see :sage_root:`build/tox.ini`
-    for details.  You should only use ``sage-bootstrap-python`` for
-    installation tasks that must be able to run before Sage has made
-    ``python3`` available.  It must not be used for running ``pip`` or
-    ``setup.py`` for any package.
-
-    ``python3`` runs the version of Python managed by Sage (either its
-    own installation of Python 3 from an SPKG or a venv over a system
-    python3.  You should use this if you are installing a Python package
+    ``python3`` runs from the venv over a system python3.
+    You should use this if you are installing a Python package
     to make sure that the libraries are installed in the right place.
 
 Many packages currently do not separate the build and install steps and only