$ git clone -n https://src.fedoraproject.org/rpms/ghc-aeson.git /var/lib/mock/f41-build-side-1-2672269-29195/root/chroot_tmpdir/scmroot/ghc-aeson
Cloning into '/var/lib/mock/f41-build-side-1-2672269-29195/root/chroot_tmpdir/scmroot/ghc-aeson'...
$ git fetch origin 0ffb28fbb36aa319e0ff6ed9e49ea657cba28c19:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-aeson
 * [new ref]         0ffb28fbb36aa319e0ff6ed9e49ea657cba28c19 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0ffb28f OneTuple-0.4.2, indexed-traversable-instances-0.1.2, semialign-1.3.1