$ git clone -n https://src.fedoraproject.org/rpms/trelby.git /var/lib/mock/f42-build-side-1-3539482-46565/root/chroot_tmpdir/scmroot/trelby
Cloning into '/var/lib/mock/f42-build-side-1-3539482-46565/root/chroot_tmpdir/scmroot/trelby'...
$ git fetch origin d2e7a588de8969fd4f38df60c0db5253b648dd76:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/trelby
 * [new ref]         d2e7a588de8969fd4f38df60c0db5253b648dd76 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d2e7a58 2.4.15