## What's Changed
Bug fixes

hash: allow unsigned int != size_t in sha256 by @ethomson in hash: allow unsigned int != size_t in sha256 libgit2/libgit2#6996
include: Fix code comment termination by @florianpircher in include: Fix code comment termination libgit2/libgit2#6997
alternates: allow relative paths in all repositories by @vapier in alternates: allow relative paths in all repositories libgit2/libgit2#7019
FIx potential null dereference by @peter15914 in FIx potential null dereference libgit2/libgit2#6998
cli: fix undefined alloca() on CYGWIN by @carlo-bramini in cli: fix undefined alloca() on CYGWIN libgit2/libgit2#7022
attr: honor ignorecase in attribute matching by @ethomson in attr: honor ignorecase in attribute matching libgit2/libgit2#7018
tag: Refuse to use HEAD as a tagname by @csware in tag: Refuse to use HEAD as a tagname libgit2/libgit2#7061
Fix memory leak in openssl fips modes by @wklatka in Fix memory leak in openssl fips modes libgit2/libgit2#7064
Fix circular includes between types.h and oid.h by @georgthegreat in Fix circular includes between types.h and oid.h libgit2/libgit2#7059
diff: correct diff stat alignment in presence of renames w/ common prefix. by @kivikakk in diff: correct diff stat alignment in presence of renames w/ common prefix. libgit2/libgit2#7057
Revert include path regression by @ytnuf in Revert include path regression libgit2/libgit2#7039

Build and CI improvements

benchmarks: update path to baseline cli by @ethomson in benchmarks: update path to baseline cli libgit2/libgit2#7006
Update SelectSSH.cmake by @lrm29 in Update SelectSSH.cmake libgit2/libgit2#7012
ci: update download-artifact version by @ethomson in ci: update download-artifact version libgit2/libgit2#7038
install cmake files into configured libdir by @kanavin in src/libgit2/CMakeLists.txt: install cmake files into configured libdir libgit2/libgit2#7004
Test updates by @ethomson in Test updates libgit2/libgit2#7025
conflict tests: check core.ignorecase by @emilazy in conflict tests: check core.ignorecase libgit2/libgit2#7026
Include common.h in version.h by @ethomson in Include common.h in version.h libgit2/libgit2#7030
clar: update to latest version by @ethomson in clar: update to latest version libgit2/libgit2#7029
Fix MSVC cross compilation by @Faless in Fix MSVC cross compilation libgit2/libgit2#7079
fuzzers: Fix CFLAGS by @nelhage in fuzzers: Fix CFLAGS libgit2/libgit2#7044
Avoid duplicate definition of git_http_auth_dummy. by @JohannesWilde in Avoid duplicate definition of git_http_auth_dummy. libgit2/libgit2#7077

Documentation improvements

docs: add update_refs as ABI breaking change by @ethomson in docs: add update_refs as ABI breaking change libgit2/libgit2#7005
docs: correct wrong docstring info for git_remote_url by @DominiqueFuchs in docs: correct wrong docstring info for git_remote_url libgit2/libgit2#7076

New Contributors

@peter15914 made their first contribution in FIx potential null dereference libgit2/libgit2#6998
@kanavin made their first contribution in src/libgit2/CMakeLists.txt: install cmake files into configured libdir libgit2/libgit2#7004
@carlo-bramini made their first contribution in cli: fix undefined alloca() on CYGWIN libgit2/libgit2#7022
@vapier made their first contribution in alternates: allow relative paths in all repositories libgit2/libgit2#7019
@emilazy made their first contribution in conflict tests: check core.ignorecase libgit2/libgit2#7026
@ytnuf made their first contribution in Revert include path regression libgit2/libgit2#7039
@DominiqueFuchs made their first contribution in docs: correct wrong docstring info for git_remote_url libgit2/libgit2#7076
@wklatka made their first contribution in Fix memory leak in openssl fips modes libgit2/libgit2#7064
@kivikakk made their first contribution in diff: correct diff stat alignment in presence of renames w/ common prefix. libgit2/libgit2#7057
@JohannesWilde made their first contribution in Avoid duplicate definition of git_http_auth_dummy. libgit2/libgit2#7077

Full Changelog: libgit2/libgit2@v1.9.0...v1.9.1

View the full release notes at https://github.com/libgit2/libgit2/releases/tag/v1.9.1.