Keystrokes plugin... and mac meta keys

looking at lines 164-169 of the keystrokes plugin src, you get:

CKEDITOR.config.blockedKeystrokes =
[
   CKEDITOR.CTRL + 66 /*B*/,
   CKEDITOR.CTRL + 73 /*I*/,
   CKEDITOR.CTRL + 85 /*U*/
]; 

Using a mac alot of those are meta instead of CRTL, looking for a place to define CKEDITOR.META so you can block the browser close/save default keybindings as users are loosing unsaved content on forms by mistake.

Digging through the src, i see where I'd define CKEDITOR.META in _source/core/dom/event.js
and adding the following around say... line 62:

      if ( this.$.metaKey )
       keystroke += CKEDITOR.META; 

would allow me to add:

CKEDITOR.META+67,
CKEDITOR.META+87

to the CKEDITOR.config.blockedKeystrokes array, any pointers on how ckeditor is packaged, or where i can make those mods on the packed version? As I bet if i mod the src they aren't really whats included.

thanks in advance,

C