$ git clone -n https://src.fedoraproject.org/rpms/perl-XML-Generator.git /var/lib/mock/f45-build-27521-624/root/chroot_tmpdir/scmroot/perl-XML-Generator
Cloning into '/var/lib/mock/f45-build-27521-624/root/chroot_tmpdir/scmroot/perl-XML-Generator'...
$ git fetch origin c68ee3d021a8873b3402be52f3109453b8961fa8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-XML-Generator
 * [new ref]         c68ee3d021a8873b3402be52f3109453b8961fa8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c68ee3d Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild