$ git clone -n https://src.fedoraproject.org/rpms/ghc-aeson-compat.git /var/lib/mock/f41-build-840261-160595/root/chroot_tmpdir/scmroot/ghc-aeson-compat
Cloning into '/var/lib/mock/f41-build-840261-160595/root/chroot_tmpdir/scmroot/ghc-aeson-compat'...
$ git fetch origin 6b571bed83cf44b3a2b60bd1e0ef2bf8bdefa00d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-aeson-compat
 * [new ref]         6b571bed83cf44b3a2b60bd1e0ef2bf8bdefa00d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6b571be bump base and base-compat bounds