$ git clone -n https://src.fedoraproject.org/rpms/oxygen-sounds.git /var/lib/mock/f42-build-side-1-3499046-45964/root/chroot_tmpdir/scmroot/oxygen-sounds
Cloning into '/var/lib/mock/f42-build-side-1-3499046-45964/root/chroot_tmpdir/scmroot/oxygen-sounds'...
$ git fetch origin afc47e32b480b8095315a0bad407423158995d6f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/oxygen-sounds
 * [new ref]         afc47e32b480b8095315a0bad407423158995d6f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at afc47e3 6.3.4