$ git clone -n https://src.fedoraproject.org/rpms/rubygem-posix-spawn.git /var/lib/mock/f40-build-772490-126420/root/chroot_tmpdir/scmroot/rubygem-posix-spawn
Cloning into '/var/lib/mock/f40-build-772490-126420/root/chroot_tmpdir/scmroot/rubygem-posix-spawn'...
$ git fetch origin ae864360cd91ccac0e65a59f1c821e5584932121:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-posix-spawn
 * [new ref]         ae864360cd91ccac0e65a59f1c821e5584932121 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ae86436 Rebuilt for https://fedoraproject.org/wiki/Changes/Ruby_3.3