$ git clone -n https://src.fedoraproject.org/rpms/ghc-boxes.git /var/lib/mock/f41-build-838899-159867/root/chroot_tmpdir/scmroot/ghc-boxes
Cloning into '/var/lib/mock/f41-build-838899-159867/root/chroot_tmpdir/scmroot/ghc-boxes'...
$ git fetch origin 90239d94e19b18c7cae88798f14f656da6c1ac3f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-boxes
 * [new ref]         90239d94e19b18c7cae88798f14f656da6c1ac3f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 90239d9 bump release