$ git clone -n https://src.fedoraproject.org/rpms/ghc-gtk3.git /var/lib/mock/f39-build-1507740-35297/root/chroot_tmpdir/scmroot/ghc-gtk3
Cloning into '/var/lib/mock/f39-build-1507740-35297/root/chroot_tmpdir/scmroot/ghc-gtk3'...
$ git fetch origin 783fa9f80d4d1681e93281c1bc0c9f4cb7a630a1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-gtk3
 * [new ref]         783fa9f80d4d1681e93281c1bc0c9f4cb7a630a1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 783fa9f https://hackage.haskell.org/package/gtk3-0.15.8/changelog