Running though https://validator.w3.org/ , the result is abysmal.
At this rate, if web browsers started requiring sites to output HTML that is somewhere in the realm of normalcy, HN would sooner shut down than consider ever updating.
> no cookie popups, no "subscribe to our newsletter" slide-ins, no phenomenon where the content loads but then a second later the page resets and re-loads the content again (probably with more ads or something)
to fix rendering layout using tables and cell width to render comment levels.
Just a few lines of CSS and Arc really. That would be a big overhaul only because HN is very small, but not that big in absolute.
.comment { font-size: 14pt; } .comhead { font-size: 12pt; }
I set this up many years ago and have not had to touch it since.
But I also find it too small on my mobile, and increasing the font size doesn't improve things, just makes it necessary to scroll sideways to read the comments.
Overall the font size settings on HN are crap. I really wish @dang would listen to the frequent complaints and fix them.
Anyway, the "errors" that OP mentions are simply just deprecated attribute styling and like, one or two instances of center tags. Hardly breaking anybody's back to continue supporting those.
Almost all of the warning and errors are related to using obsolete Element attributes and invalid <table> definitions. Those shouldn't need any larger rework to clean up.
I don't say this trying to imply that HN needs to fix these or are being lazy in not doing it. YC has priorities and provide HN for free. It's totally up to them whether fixes are worth it, I just wouldn't expect it to be a huge lift.
A semantically correct HTML would be something like a frontpage with an <ol> and the comment section would be a series of nested <article> each with a <header> containing the author a <time> and an extra bonus if the parent/context/sibling links can go under a <nav>. And the separators between the header elements should not be a text content pipe character `|` but rather a CSS border-inline-start: 1px solid currentcolor;
A minimal and semantically correct HTML does not only offer superior experience for users of assistive technology, it also make your page machine readable, so users can install browser plugins to e.g. do something useful with the <time> element, and ultimately makes your page much easier to style with CSS.
Whoever is currently maintaining the codebase has taken years. They have been making changes to the HTML of the site: SVGs were added for the voting arrows as the first example I can think of, so its not like its being left to languish completely. They just don't care.