$ git clone -n https://src.fedoraproject.org/rpms/clang.git /var/lib/mock/f41-build-side-1-3061149-38478/root/chroot_tmpdir/scmroot/clang
Cloning into '/var/lib/mock/f41-build-side-1-3061149-38478/root/chroot_tmpdir/scmroot/clang'...
$ git fetch origin 3306de30342a5dfb9d329935ed7aa8371bb0d088:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/clang
 * [new ref]         3306de30342a5dfb9d329935ed7aa8371bb0d088 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3306de3 Merged into llvm package