$ git clone -n https://src.fedoraproject.org/rpms/ghc-dec.git /var/lib/mock/f40-build-742695-110881/root/chroot_tmpdir/scmroot/ghc-dec
Cloning into '/var/lib/mock/f40-build-742695-110881/root/chroot_tmpdir/scmroot/ghc-dec'...
$ git fetch origin 5ede78ef00f5c857a5654e2f021ca2ef574af2bd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-dec
 * [new ref]         5ede78ef00f5c857a5654e2f021ca2ef574af2bd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5ede78e revision and boring-0.2.1