Backported PRs:
- [x] #50637 <!-- Remove SparseArrays legacy code -->
- [x] #50665 <!-- print `@time` msg into print buffer -->
- [x] #50523 <!-- Avoid generic call in most cases for getproperty -->
- [x] #50635 <!-- `versioninfo()`: include build info and unofficial
warning -->
- [x] #50670 <!-- Make reinterpret specialize fully. -->
- [x] #50666 <!-- include `--pkgimage=no` caches for stdlibs -->
- [x] #50765 
- [x] #50764
- [x] #50768
- [x] #50767
- [x] #50618 <!-- inference: continue const-prop' when concrete-eval
returns non-inlineable -->
- [x] #50689 <!-- Attach `tanpi` docstring to method -->
- [x] #50671 <!-- Fix rdiv of complex lhs by real factorizations -->
- [x] #50598 <!-- only limit types in stack traces in the REPL -->
- [x] #50766 <!-- Don't partition alwaysinline functions -->
- [x] #50771 <!-- re-allow non-string values in ENV `get!` -->
- [x] #50682 <!-- Add fallback if we have make a weird GC decision. -->
- [x] #50781 <!-- fix `bit_map!` with aliasing -->
- [x] #50172 <!-- print feature flags used for matching pkgimage -->
- [x] #50844 <!-- Bump OpenBLAS binaries to use the new GEMM
multithreading threshold -->
- [x] #50826 <!-- Update dependency builds -->
- [x] #50845 <!-- fix #50438, use default pool for at-threads -->
- [x] #50568 <!-- `Array(::AbstractRange)` should return an `Array` -->
- [x] #50655 <!-- fix hashing regression. -->
- [x] #50779 <!-- Minor refactor to image generation -->
- [x] #50791 <!-- Make symbols internal in jl_create_native, and only
externalize them when partitioning -->
- [x] #50724 <!-- Merge opaque closure modules with the rest of the
workqueue -->
- [x] #50738 <!-- Add alignment to constant globals -->
- [x] #50871 <!-- macOS: Don't inspect dead threadtls during exception
handling. -->

Need manual backport:

Contains multiple commits, manual intervention needed:

Non-merged PRs with backport label:
- [ ] #50850 <!-- Remove weird Rational dispatch and add pi functions to
list -->
- [ ] #50823 <!-- Make ranges more robust with unsigned indexes. -->
- [ ] #50809 <!-- Limit type-printing in MethodError -->
- [ ] #50663 <!-- Fix Expr(:loopinfo) codegen -->
- [ ] #50594 <!-- Disallow non-index Integer types in isassigned -->
- [ ] #50385 <!-- Precompile pidlocks: add to NEWS and docs -->
- [ ] #49805 <!-- Limit TimeType subtraction to AbstractDateTime -->

Backported PRs:
- [x] #48625 <!-- add replace(io, str, patterns...) -->
- [x] #48387 <!-- Improve documentation of sort-related functions -->
- [x] #48363 <!-- Revise sort.md and docstrings in sort.jl -->
- [x] #48977 <!-- Update SparseArrays.jl stdlib for SuiteSparse 7 -->
- [x] #50719 <!-- fix `CyclePadding(::DataType)` -->
- [x] #50694 <!-- inference: permit recursive type traits -->
- [x] #50860 <!-- Add `Base.get_extension` to docs/API -->
- [x] #50594 <!-- Disallow non-index Integer types in isassigned -->
- [x] #50802 <!-- Makes IntrusiveLinkedListSynchronized mutable to avoid
allocation on poptask -->
- [x] #50858 <!-- Add a `threadpool` parameter to `Channel` constructor
-->
- [x] #50874 <!-- Restrict COFF to a single thread when symbol count is
high -->
- [x] #50822 <!-- Add default method for setmodifiers! -->
- [x] #50730 <!-- Fix integer overflow in `isapprox` -->
- [x] #50850 <!-- Remove weird Rational dispatch and add pi functions to
list -->
- [x] #50809 <!-- Limit type-printing in MethodError -->
- [x] #50915 <!-- Add note the `Task` about sticky bit -->
- [x] #50929 <!-- when widening tuple types in tmerge, only widen the
complex parts -->
- [x] #50928 <!-- Bump JuliaSyntax to 0.4.6 -->
- [x] #50959 <!-- Update libssh2 patches -->
- [x] #50823 <!-- Make ranges more robust with unsigned indexes. -->
- [x] #48542 <!-- Add docs on task-specific buffering using
multithreading -->
- [x] #50912 <!-- Separate foreign threads into a :foreign threadpool
-->
- [x] #51010 <!-- Add ORIGIN to SuiteSparse rpath on Linux/FreeBSD -->
- [x] #50753 <!-- cat: remove unused promote_eltype methods that confuse
inference -->
- [x] #51027 <!-- Implement realloc accounting correctly -->
- [x] #51019 <!-- fix a case of potentially use of undefined variable
when handling error in distributed message processing -->
- [x] #51039 <!-- Revert "Optimize findall(f, ::AbstractArray{Bool})
(#42202)" -->
- [x] #51036 <!-- add missing invoke edge for nospecialize targets -->
- [x] #51042 <!-- inference: fix return_type_tfunc modeling of concrete
functions -->
- [x] #51114 <!-- Workaround upstream FreeBSD issue #272992 -->
- [x] #50892 <!-- Add `JL_DLLIMPORT` to `small_typeof` declaration -->
- [x] #51154 <!-- broadcast: use recursion rather than ntuple to map
over a tuple -->
- [x] #51153 <!-- fix debug typo in "add missing invoke edge for
nospecialize targets (#51036)" -->
- [x] #51222 <!-- Check again if the tty is open inside the IO lock -->
- [x] #51236 <!-- Add lock around uv_unref during init -->
- [x] #51243 <!-- GMP: Gracefully handle more overflows. -->
- [x] #51254 <!-- Ryu: make sure adding zeros does not overwrite
trailing dot -->
- [x] #51175 <!-- shorten stale_age for cachefile lock -->
- [x] #51300 <!-- fix method definition error for bad vararg -->
- [x] #51307 <!-- fix force-throw ctrl-C on Windows -->
- [x] #51303 <!-- ensure revising structs is safe -->
- [x] #51393 
- [x] #51403 

Need manual backport:
- [x] #51009 <!-- fix #50562, regression in `in` of tuple of Symbols -->
- [x] #51053 <!-- Bump Statistics stdlib -->
- [x] #51013 <!-- fix #50709, type bound error due to free typevar in
sparam env -->
- [x] #51305 <!-- reduce test time for rounding and floatfuncs -->

Contains multiple commits, manual intervention needed:
- [ ] #50663 <!-- Fix Expr(:loopinfo) codegen -->
- [ ] #51035 <!-- refactor GC scanning code to reflect jl_binding_t are
now first class -->
- [ ] #51092 <!-- inference: fix bad effects for recursion -->
- [x] #51247 <!-- Check if malloc has succeeded before incrementing gc
stats -->
- [x] #51294 <!-- use LibGit2_jll for LibGit2 library -->

Non-merged PRs with backport label:
- [ ] #51132 <!-- Handle `AbstractQ` in concatenation -->
- [x] #51029 <!-- testdefs: make sure that if a test set changes the
active project, they change it back when they're done -->
- [ ] #50919 <!-- Code loading: do the "skipping mtime check for stdlib"
check regardless of the value of `ispath(f)` -->
- [ ] #50824 <!-- Add some aliasing warnings to docstrings for mutating
functions -->
- [x] #50385 <!-- Precompile pidlocks: add to NEWS and docs -->
- [ ] #49805 <!-- Limit TimeType subtraction to AbstractDateTime -->