$ git clone -n https://src.fedoraproject.org/rpms/perl-Test-Unit.git /var/lib/mock/f45-build-26938-620/root/chroot_tmpdir/scmroot/perl-Test-Unit
Cloning into '/var/lib/mock/f45-build-26938-620/root/chroot_tmpdir/scmroot/perl-Test-Unit'...
$ git fetch origin 4f7162a38c4bcd22ce017d592980afa1c29cd72a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Test-Unit
 * [new ref]         4f7162a38c4bcd22ce017d592980afa1c29cd72a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4f7162a Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild