In the future there might be a file version with IE11 and without IE11 support. IE11 is currently at 3,7% globally, so I still see considerable use there.
Thanks for the tip, I'll be improving that in the patch releases soon.
Until that is done: It supports IE11, FF48+, Edge and Chrome. Mobile browser tests are on the way. Some things are ported from Normalize.css for backword compatibility, but the goal is to remove them as soon as IE11 drops below 1%.