$ git clone -n https://src.fedoraproject.org/rpms/rubygem-rack-test.git /var/lib/mock/f40-build-2323293-58706/root/chroot_tmpdir/scmroot/rubygem-rack-test
Cloning into '/var/lib/mock/f40-build-2323293-58706/root/chroot_tmpdir/scmroot/rubygem-rack-test'...
$ git fetch origin b51429fc88ad56afe94eec4dec9bfee9eaeeda70:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-rack-test
 * [new ref]         b51429fc88ad56afe94eec4dec9bfee9eaeeda70 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b51429f Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild