$ git clone -n https://src.fedoraproject.org/rpms/flatpak-kcm.git /var/lib/mock/f42-build-side-1-3539963-46572/root/chroot_tmpdir/scmroot/flatpak-kcm
Cloning into '/var/lib/mock/f42-build-side-1-3539963-46572/root/chroot_tmpdir/scmroot/flatpak-kcm'...
$ git fetch origin 8970a5a85682765974f210859ebc4b2ead24bd52:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/flatpak-kcm
 * [new ref]         8970a5a85682765974f210859ebc4b2ead24bd52 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8970a5a 6.3.5