$ git clone -n https://src.fedoraproject.org/rpms/libsass.git /var/lib/mock/f40-build-785925-134137/root/chroot_tmpdir/scmroot/libsass
Cloning into '/var/lib/mock/f40-build-785925-134137/root/chroot_tmpdir/scmroot/libsass'...
$ git fetch origin acd4f45aa300063c101faf3c4ffd84a0305e9d34:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libsass
 * [new ref]         acd4f45aa300063c101faf3c4ffd84a0305e9d34 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at acd4f45 Update to 3.6.6 (close RHBZ#1963228)