$ git clone -n https://src.fedoraproject.org/rpms/trademgen.git /var/lib/mock/f42-build-886905-187831/root/chroot_tmpdir/scmroot/trademgen
Cloning into '/var/lib/mock/f42-build-886905-187831/root/chroot_tmpdir/scmroot/trademgen'...
$ git fetch origin 6abb8fca542aa27a88172a4d0ae973818385e731:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/trademgen
 * [new ref]         6abb8fca542aa27a88172a4d0ae973818385e731 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6abb8fc Upstream update