x-meta-keysym

x-meta-keysym is a variable defined in `C source code'.
Its value is

nil

Documentation:
Which keys Emacs uses for the meta modifier.
This should be one of the symbols `alt', `hyper', `meta', `super'.
For example, `meta' means use the Meta_L and Meta_R keysyms. The
default is nil, which is the same as `meta'.