Currently there are some browser blacklists in different modules of WikiEditor, which are partially useless. For example,
jquery.wikiEditor.js blacklists IE < 7, FF < 2, and Opera < 9.6. But in startup.js from RessourceLoader these browsers are blacklisted anyway, actually IE < 8, FF < 3, and Opera < 12 won't get any JS.

On the other hand, some blacklisted browsers from WikiEditor should probably be added to the global blacklist: When Safari < 3, Chrome < 3, and Netscape < 9 were broken and thus blacklisted for WikiEditor years ago, it is probably a good idea not to give them any JS nowadays.