$ git clone -n https://src.fedoraproject.org/rpms/ghc-kan-extensions.git /var/lib/mock/f39-build-1972966-43327/root/chroot_tmpdir/scmroot/ghc-kan-extensions
Cloning into '/var/lib/mock/f39-build-1972966-43327/root/chroot_tmpdir/scmroot/ghc-kan-extensions'...
$ git fetch origin e6c46cc7f1c47c74826430d8084084a6252f1e3d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-kan-extensions
 * [new ref]         e6c46cc7f1c47c74826430d8084084a6252f1e3d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e6c46cc revised .cabal files