$ git clone -n https://src.fedoraproject.org/rpms/jacop.git /var/lib/mock/f42-build-3346771-45002/root/chroot_tmpdir/scmroot/jacop
Cloning into '/var/lib/mock/f42-build-3346771-45002/root/chroot_tmpdir/scmroot/jacop'...
$ git fetch origin 4fe6b54abbc9c169ef51b6b3eef53af60325e02f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jacop
 * [new ref]         4fe6b54abbc9c169ef51b6b3eef53af60325e02f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4fe6b54 Orphaned for 6+ weeks