$ git clone -n https://src.fedoraproject.org/rpms/ghc-hashable.git /var/lib/mock/f40-build-742182-110610/root/chroot_tmpdir/scmroot/ghc-hashable
Cloning into '/var/lib/mock/f40-build-742182-110610/root/chroot_tmpdir/scmroot/ghc-hashable'...
$ git fetch origin 65c06dbd800e2e92ef1c671dd7cc8e5497fa30d4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-hashable
 * [new ref]         65c06dbd800e2e92ef1c671dd7cc8e5497fa30d4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 65c06db drop data-array-byte