$ git clone -n https://src.fedoraproject.org/rpms/oxygen-sounds.git /var/lib/mock/f42-build-side-1-3541401-46580/root/chroot_tmpdir/scmroot/oxygen-sounds
Cloning into '/var/lib/mock/f42-build-side-1-3541401-46580/root/chroot_tmpdir/scmroot/oxygen-sounds'...
$ git fetch origin d400947ad82a71bab27017111be3e31e65a1723d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/oxygen-sounds
 * [new ref]         d400947ad82a71bab27017111be3e31e65a1723d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d400947 6.3.5