What is keyboard-local?

[Xue Fuqiao]

In the docstring of the variable `key-translation-map':

  This keymap works like `function-key-map', but comes after that,
  and its non-prefix bindings override ordinary bindings.
  Another difference is that it is global rather than keyboard-local.

What does the "keyboard-local" mean here?  I have searched the Emacs manuals, 
Emacs FAQ, and the archive of this newsgroup, but I don't find anything useful. 
 Can anybody help?  Thanks.

-- 
Best regards, Xue Fuqiao.
http://www.emacswiki.org/emacs/XueFuqiao