Yep, that edition.png gives so much more possibilities for resource pack makers: finally you can give the game your own official subtitle:
"The one, the only, the proud"
And for our beloved complainers, you can have:
"Sadly not beta 1.7.3"
"The lousy combat edition"
"Down with Microsoft"
Or you can of course just leave it empty, so that you don't have a subtitle anymore, like I have done.