$ git clone -n https://src.fedoraproject.org/rpms/perl-B-Keywords.git /var/lib/mock/f45-build-21846-588/root/chroot_tmpdir/scmroot/perl-B-Keywords
Cloning into '/var/lib/mock/f45-build-21846-588/root/chroot_tmpdir/scmroot/perl-B-Keywords'...
$ git fetch origin b93bb84a7bf763aacb93a4a08b0544fd0284e11c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-B-Keywords
 * [new ref]         b93bb84a7bf763aacb93a4a08b0544fd0284e11c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b93bb84 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild