$ git clone -n https://src.fedoraproject.org/rpms/rubygem-unf_ext.git /var/lib/mock/f40-build-2224258-52777/root/chroot_tmpdir/scmroot/rubygem-unf_ext
Cloning into '/var/lib/mock/f40-build-2224258-52777/root/chroot_tmpdir/scmroot/rubygem-unf_ext'...
$ git fetch origin 2ce9ba89043bc18e872c24ce2dae5a99b8a326e7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-unf_ext
 * [new ref]         2ce9ba89043bc18e872c24ce2dae5a99b8a326e7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2ce9ba8 Rebuild for https://fedoraproject.org/wiki/Changes/Ruby_3.3