$ git clone -n https://src.fedoraproject.org/rpms/perl-String-Errf.git /var/lib/mock/f45-build-26281-616/root/chroot_tmpdir/scmroot/perl-String-Errf
Cloning into '/var/lib/mock/f45-build-26281-616/root/chroot_tmpdir/scmroot/perl-String-Errf'...
$ git fetch origin 5c3f1e60a6d0099ebfa20616e89b0575d3ae7d31:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-String-Errf
 * [new ref]         5c3f1e60a6d0099ebfa20616e89b0575d3ae7d31 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5c3f1e6 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild