Firefox has supported MathML for a very long time. And I think chrome had an experimental version it for a while then removed it. I wouldn't hold my breath waiting for universal browser support.
Igalia picked up the Chromium development, they actually have it in an amazingly good state at this point. This image compares rendering from Chromium with their patches, Safari, and Firefox (in that order) https://mathml.igalia.com/img/mathml-example-gamma.png
That being said I wouldn't hold my breath it'll ship this year either since there is still some work in LayoutNG to be completed at minimum but maybe 2022 we'll all be amazed it finally happened.
That being said I wouldn't hold my breath it'll ship this year either since there is still some work in LayoutNG to be completed at minimum but maybe 2022 we'll all be amazed it finally happened.