If I understand this correctly Xi and Alacritty are both using OpenGL to do the rendering and recently I heard that Rust supports compiling to Web Assembly.
Sounds as if it should be easy to port those apps to the browser world (WebGL + Web Assembly)? Does anybody know of any plans to do just that?
"Easy" is not the right word for this, but it's possible. One challenge is that browsers don't export an interface for "shaping". For Latin script, that means kerning and ligatures, and for complex scripts, it means being able to render it correctly at all. Currently, alacritty doesn't really deal with this, but xi-mac does, using the interfaces provided by Core Text.
That's where pathfinder [1] comes in, as the fastest font rasterizer, utilizing the GPU and built in rust. (not affiliated). Ok maybe I'm overselling just a little but it's exciting!