$ git clone -n https://src.fedoraproject.org/rpms/perl-XML-Writer.git /var/lib/mock/f45-build-27585-625/root/chroot_tmpdir/scmroot/perl-XML-Writer
Cloning into '/var/lib/mock/f45-build-27585-625/root/chroot_tmpdir/scmroot/perl-XML-Writer'...
$ git fetch origin c91b18b778149d087e9de84a2cc3cd1660a5b519:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-XML-Writer
 * [new ref]         c91b18b778149d087e9de84a2cc3cd1660a5b519 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c91b18b Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild