$ git clone -n https://src.fedoraproject.org/rpms/ghc-extensible-exceptions.git /var/lib/mock/f41-build-837643-159296/root/chroot_tmpdir/scmroot/ghc-extensible-exceptions
Cloning into '/var/lib/mock/f41-build-837643-159296/root/chroot_tmpdir/scmroot/ghc-extensible-exceptions'...
$ git fetch origin e4e15f23ccc189c65dd1d34f079ad256b803ca56:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-extensible-exceptions
 * [new ref]         e4e15f23ccc189c65dd1d34f079ad256b803ca56 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e4e15f2 bump release