$ git clone -n https://src.fedoraproject.org/rpms/libguestfs.git /var/lib/mock/f40-build-2588104-62530/root/chroot_tmpdir/scmroot/libguestfs
Cloning into '/var/lib/mock/f40-build-2588104-62530/root/chroot_tmpdir/scmroot/libguestfs'...
$ git fetch origin 89084e10d2131f24b084fd9b010794746023a9e2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libguestfs
 * [new ref]         89084e10d2131f24b084fd9b010794746023a9e2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 89084e1 Use make macros