$ git clone -n https://src.fedoraproject.org/rpms/llvm.git /var/lib/mock/f41-build-side-1-2812346-32939/root/chroot_tmpdir/scmroot/llvm
Cloning into '/var/lib/mock/f41-build-side-1-2812346-32939/root/chroot_tmpdir/scmroot/llvm'...
$ git fetch origin 4251de274bf3c0eb5e395fa5234716df5acd30d7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/llvm
 * [new ref]         4251de274bf3c0eb5e395fa5234716df5acd30d7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4251de2 Add #region #endregion comments