Description

The HTML specification contains a section on "Other Embedded Content", specifically integrating SVG and MathML into the parser. However, these co-evolved and were radically different in many ways from the rest of the platform which got all of the attention. For the last 4 years or so, much work has gone into alignment with the platform (DOM/IDL, CSS) and both internal and developer-facing improvements, as well as spec updates.

Things are very much improved, generally, but we still have ragged edges that need attention. This would focus on increasing interoperability of MathML-Core support and specific new platform integrations, as well as improving SVG interop.

Rationale

I believe that 2023 is an ideal time to focus on interoperability improvements in both, with so much aligning in terms of new implementations and internal improvements finally making it possible to set these other two forms back on a stable footing as part of one platform. They are, in my opinion, super important and historically unique - being the only other languages that have gained wide support.

Specification

• https://w3c.github.io/mathml-core/ (about to CR, but it is partially a subset with much of it having wide implementation for years in 2/3 engines)
• https://www.w3.org/TR/SVG/
• https://html.spec.whatwg.org/
• https://www.w3.org/TR/css-fonts-4/

Tests

https://wpt.fyi/results/mathml?label=master&label=experimental&aligned&view=subtest&q=mathml

https://wpt.fyi/results/?label=master&label=experimental&aligned&view=subtest&q=svg (we could chose a subset, as I did with MathML tests above)