$ git clone -n https://src.fedoraproject.org/rpms/rubygem-eventmachine.git /var/lib/mock/f40-build-747582-113311/root/chroot_tmpdir/scmroot/rubygem-eventmachine
Cloning into '/var/lib/mock/f40-build-747582-113311/root/chroot_tmpdir/scmroot/rubygem-eventmachine'...
$ git fetch origin 6565ae28fda31846f79ed161f6128df8ca02a73a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-eventmachine
 * [new ref]         6565ae28fda31846f79ed161f6128df8ca02a73a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6565ae2 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild