$ git clone -n https://src.fedoraproject.org/rpms/libserializer.git /var/lib/mock/f41-build-1022169-18052/root/chroot_tmpdir/scmroot/libserializer
Cloning into '/var/lib/mock/f41-build-1022169-18052/root/chroot_tmpdir/scmroot/libserializer'...
$ git fetch origin aad1fd58964f9b3b50fbe5d3d0cc79300e12cbc3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libserializer
 * [new ref]         aad1fd58964f9b3b50fbe5d3d0cc79300e12cbc3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at aad1fd5 Eliminate use of obsolete %patchN syntax (#2283636)