$ git clone -n https://src.fedoraproject.org/rpms/libserializer.git /var/lib/mock/f45-build-16957-494/root/chroot_tmpdir/scmroot/libserializer
Cloning into '/var/lib/mock/f45-build-16957-494/root/chroot_tmpdir/scmroot/libserializer'...
$ git fetch origin 2b23ae28620216f153bac5d19873dfb91f96788e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libserializer
 * [new ref]         2b23ae28620216f153bac5d19873dfb91f96788e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2b23ae2 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild