Wow...
...what a clever idea. Fixing stuff rather than adding more bloat no one wants.
While its managers squabble, engineers at Microsoft and Google have put their heads together to ease some of the more severe developer pain points in browsers. Spoiler: it involves CSS. Those who remember Microsoft's shenanigans during the heyday of Internet Explorer will doubtless be feeling a twinge of irony at the thought …
I thought the web had documented standards that browser developers were expected to follow. It appears I was wrong. It seems that browser developers are creating the standards the web finds itself obliged to follow. What's worse, different browser developers are tinkering with the standards in competition with each other. This attempt at "compatibility" merely highlights (and maybe attempts to partially rectify) the problem they've created in the first place.
None of this is really for us the users - it's "competition".
The annoying thing about standards is that they're written by humans. That means that at some level there is ambiguity. If different vendors produce software to different interpretations of the standards, but both 'correct', that's not entirely their fault.
Working together to reach a common understanding of how to interpret the standard (ie resolve the ambiguity) is A Good Thing.
Then there are the extensions which are useful but bleeding-edge, which they want to try out before codifying a standard for. Work out the bugs, document it, then get others to adopt it. It might not be the ideal workflow, but I can't see how you can get around that without stifling innovation.
As someone who's been building websites for 20+ years, I can tell you that things are a hell of a lot better now than they ever were before!
"Working together to reach a common understanding of how to interpret the standard (ie resolve the ambiguity) is A Good Thing."
I've mentioned elsewhere my travails with Flexbox, and with the fact that three major browser makers all agreed on one interpretation of one word in the standard, but Google's guy did a Humpty-dumpty and said "it means just what I choose it to mean—neither more nor less."
Three-some years later he left Google, and fast-forward a few months the mis-implementation got fixed. "Working together" is a very good thing.
BTW: I didn't see mentioned here that for something to become a standard feature it has to be implemented by at least two different vendors, and nominally compatibly. That the edge cases come out after the standards do is unfortunate, but I don't know a process that would reliably avoid that on such a large stage as the world.
It is corruption of the standards. Look at all the crap Google has shoehorned in to web standards, like standards based ways to access USB devices from a browser. How many times do we have to tell them, we don't want a browser to be an operating system!
Fortunately not everyone implements those "standards", but then when you have efforts to measure how "standard" a browser is in comparison to other browsers, the one that smartly omits such crap looks like it is behind when it is in fact ahead when it comes to security/privacy.