Is this really a hard problem? Rendering some text with coloring?

I believe we're just making everything harder than it needs by constraining it to a browser interface. This would be trivial as a terminal application written in native code.

Yeah, my bad. Sorry i wasted your time :(

What are you even talking about, this post is about rendering code diffs in the context of the web.

Whether or not it would be "trivial" in a native terminal application is irrelevant.