I think I'll list out the components of a browser engine to see if I get any bites:
* URI parser
* HTTP client
* HTML parser
* CSS engine
* Block layout
* Inline layout (this is where all the inherent complexity lies, but it's not hard to create something Euro-centric)
* Rendering
* Hooking this pipeline together
Moving beyond the basics of rendering to an image:
* Event dispatch/handling
* Forms
* A browser UI
Anyone interested in tackling any of these?
As for what exists already:
* I've implemented a CSS engine
* Most languages have a URI parser, HTTP client, and HTML parser
* GNOME's Pango can be used for inline layout at least starting off
* Servo's WebRender or GNOME's GSK implements GPU-rendering of the CSS Box Model
The caveat on Pango though is that it would need to be reimplemented in order to support things like floats and webfonts, that's explicitly out of scope for them.
@zachdecook It would be reasonable to say "here's the things we don't support on principle, and here's the things we're struggling with."