$ git clone -n https://src.fedoraproject.org/rpms/perl-DateTime-Calendar-Julian.git /var/lib/mock/f45-build-23054-595/root/chroot_tmpdir/scmroot/perl-DateTime-Calendar-Julian
Cloning into '/var/lib/mock/f45-build-23054-595/root/chroot_tmpdir/scmroot/perl-DateTime-Calendar-Julian'...
$ git fetch origin 89a1866736d971f938629846c9df5136537fc0ff:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-DateTime-Calendar-Julian
 * [new ref]         89a1866736d971f938629846c9df5136537fc0ff -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 89a1866 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild