$ git clone -n https://src.fedoraproject.org/rpms/389-ds-base.git /var/lib/mock/f42-build-side-1-3501680-45976/root/chroot_tmpdir/scmroot/389-ds-base
Cloning into '/var/lib/mock/f42-build-side-1-3501680-45976/root/chroot_tmpdir/scmroot/389-ds-base'...
$ git fetch origin d3ac5c9409e60c7fda1a1295f1302b86a0bd9775:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/389-ds-base
 * [new ref]         d3ac5c9409e60c7fda1a1295f1302b86a0bd9775 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d3ac5c9 Update to 3.1.2-4