$ git clone -n https://src.fedoraproject.org/rpms/ghc-data-default-instances-containers.git /var/lib/mock/f40-build-2047881-48977/root/chroot_tmpdir/scmroot/ghc-data-default-instances-containers
Cloning into '/var/lib/mock/f40-build-2047881-48977/root/chroot_tmpdir/scmroot/ghc-data-default-instances-containers'...
$ git fetch origin 267b6520e1e1460cceb4bcfe11eb178bebe39703:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-data-default-instances-containers
 * [new ref]         267b6520e1e1460cceb4bcfe11eb178bebe39703 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 267b652 bump release