[dginev]

Right, that's LaTeXML - it tries to emulate as much as possible of the TeX typesetting system, while retaining enough control to emit structured markup.

Which also allows us (and generally all contributors of latexml package support) to conveniently maintain various parallel data structures and metadata needed along the way.

Modern HTML is very often helpful to produce higher quality article renderings. Examples:

1. we recently started using flexbox for subfigures, allowing them to reflow.

2. we have started emitting ARIA accessibility annotations (there is now an "alt" key for \includegraphics)

3. MathML Core allowed us to have native web rendering for math expressions in every browser.

As to LaTeX rendering in the browser, there are various other projects out there you could look up with partial support. For latexml the WebAssembly route seems most realistic, as we are undergoing a rewrite in Rust. But there are quite a number of pieces to flesh out before we get there.