Here’s another story of Bocoup doing that, this time for the
appearance property. The story is told in a Twitter thread, but the thread is broken somehow (looks like a deleted Tweet), so your best bet is to go to this one, then scroll up and down to see the whole thing. Gosh, I hope they blog it.
It took literally years of work:
2 years ago, @firefox asked us to work on a project to fix problems within the CSS appearance property. The issue came when we found out that each browser has its own implementation of how the appearance property should work on forms.
They had to do tons of research, write tests, and ultimately overhaul HTML and CSS specs. Then they needed to prove that, with those changes, browsers could un-prefix the property without breaking websites — the first attempt at this broke websites and was reverted. Then they actually get all three major browsers to do it. (Landed in Chrome, Firefox is on it, Safari has an open bug, and there is public desire to coordinate a release.)
Really goes to show just how long and grueling this work can be because it’s so crucial to get it right. If you’re into this stuff, listen to ShopTalk 407 with Brian Kardell.