Filtering by browser is a throwback
... to 2001 when IE6 was released and so many websites wanted to make a point that they no longer want to talk with IE4 or IE5. Now we have HTML5 universally supported by almost all browsers, and I frankly am fed up with web developers making a stance "No, we are special because something something something". No you bloody are not, you are just ignorant git!
Particularly good (bad?) example is Barclays banking - connect from Linux Opera or Firefox, current stable version, and it will suggest that my web browser is obsolete and I should use (possibly older, but hey, running on Windows!) versions of Chrome or ... Firefox. At the same time when trying to stuff 15 tracking cookies from 3rd parties on my computer - because it's only banking! Duh!