> it's impossible to make a modern one that supports all sites without those human resources.

Then let's not - death to irregular HTML and let the era of lean browsers begin !

Yes, I know, Martian Headsets (https://www.joelonsoftware.com/2008/03/17/martian-headsets/) - but considering how much of a contemporary web browser is about supporting irregular markup and other grandfathered hacks, deliberately scoping them out is an exciting approach to a possible non-RFC793 compliant future. Won't fly with mass market, but worth exploring by people who don't care about the mass market - and the marketing will come later, once someone with no money and a device to ship figures out how fast such browser can be with ridiculously low resources !

For sure. There's also a big question of what "support" means.

If rendering is usable but not pixel-perfect, then maybe that's fine. Especially when what's being rendered is in categories like "visual fluff" and "needed for advertising".

As much as I love personal projects, if you want something to survive it needs industry support, that's how Linux and Python are still going.

Who's going to support a browser compatible with stuff from 2011? There are companies like Ekioh that make niche solutions for embedded stuff, but there's nothing open source.

The specs are pretty good though in that most of the handling of mangled HTML is actually defined in the spec. So while the specs are enormous, simply implementing exactly what they say to implement can get you most of the way there.

> You can make "a browser", but it's impossible to make a modern one that supports all sites

So what? Interested people can have multiple browsers installed.

Not even Firefox is supported by all sites, in which case I dust off Chromium I keep installed for just such situations.