$ git clone -n https://src.fedoraproject.org/rpms/libguestfs.git /var/lib/mock/f41-build-821676-152618/root/chroot_tmpdir/scmroot/libguestfs
Cloning into '/var/lib/mock/f41-build-821676-152618/root/chroot_tmpdir/scmroot/libguestfs'...
$ git fetch origin dff1c1d43171827c90ab54fc5d7a16bef9c109be:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libguestfs
 * [new ref]         dff1c1d43171827c90ab54fc5d7a16bef9c109be -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dff1c1d New upstream development version 1.53.5