$ git clone -n https://src.fedoraproject.org/rpms/ghc-IOSpec.git /var/lib/mock/f41-build-839145-160038/root/chroot_tmpdir/scmroot/ghc-IOSpec
Cloning into '/var/lib/mock/f41-build-839145-160038/root/chroot_tmpdir/scmroot/ghc-IOSpec'...
$ git fetch origin 8ab0b88ab5e6939e0caf9f0d4dbd46cae72d3a7b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-IOSpec
 * [new ref]         8ab0b88ab5e6939e0caf9f0d4dbd46cae72d3a7b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8ab0b88 https://hackage.haskell.org/package/IOSpec-0.3.1.2/changelog