I wondered about that, since the original document obviously was a pdf. Anyways, doesn't matter because your fork did the right thing for me on 24" @1920x1200, while i've been up for about 7 hours, reading and beginning to feel a little tired. When i came across your's it eased me into focus. Again: This is how it should be!

edit: i should add i know both the internal ones of Firefox, and Chromium. They usually don't work for me, that is why i disabled them, apart from the usual cargo-culting paranoia to only open documents with native applications ;)