Meta + shift + Fn combos are recognized by xterm>=216.
They are useful. Its good if they are included in
xterm-alternatives-map.

In GNU Emacs 25.0.91.1 (x86_64-pc-linux-gnu, GTK+ Version 2.24.29)
Repository revision: 52f64cc2e74ab83752c8f2d37ef0fc6df5ef8b30