$ git clone -n https://src.fedoraproject.org/rpms/ghc-what4.git /var/lib/mock/f41-build-857404-168079/root/chroot_tmpdir/scmroot/ghc-what4
Cloning into '/var/lib/mock/f41-build-857404-168079/root/chroot_tmpdir/scmroot/ghc-what4'...
$ git fetch origin ef40a1a22e7e8c573925d3150257cc6314479f17:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-what4
 * [new ref]         ef40a1a22e7e8c573925d3150257cc6314479f17 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ef40a1a Fix missing entry in `sources` and `.gitignore` files.