$ git clone -n https://src.fedoraproject.org/rpms/ghc-hostname.git /var/lib/mock/f41-build-837626-159296/root/chroot_tmpdir/scmroot/ghc-hostname
Cloning into '/var/lib/mock/f41-build-837626-159296/root/chroot_tmpdir/scmroot/ghc-hostname'...
$ git fetch origin 9fd86e330dd7b4393bea58edcd83d751d5f98a8f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-hostname
 * [new ref]         9fd86e330dd7b4393bea58edcd83d751d5f98a8f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9fd86e3 bump release