Emacs has been violating the GPL since 2009
An embarrassing mishap at the Free Software Foundation has seen the Emacs editor become GPL-violating software. In the process of merging CEDET into Emacs 24, it was noted that a number of compiled CEDET parsers were missing their associated grammar files and parser generators. One developer pointed out that this was in conflict with the GPL that Emacs is licensed under, and Richard Stallman, who stepped down from Emacs maintenance in 2008, intervened calling it "a very bad mistake".
The compiled files in question are not the "binary blob" files of uneditable bytes that are often the cause of issues like this, but files of code which were generated by a code generating tool.