$ git clone -n https://src.fedoraproject.org/rpms/rubygem-glib2.git /var/lib/mock/f40-build-2224126-52769/root/chroot_tmpdir/scmroot/rubygem-glib2
Cloning into '/var/lib/mock/f40-build-2224126-52769/root/chroot_tmpdir/scmroot/rubygem-glib2'...
$ git fetch origin 6b7c4a5dc3f88e6486aa6fbb80ccc69dbfb254f3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-glib2
 * [new ref]         6b7c4a5dc3f88e6486aa6fbb80ccc69dbfb254f3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6b7c4a5 Rebuild for https://fedoraproject.org/wiki/Changes/Ruby_3.3