Not sure that is fair; Google push updates to Webkit all the time, but naturally they develop them on their fork.

The other vendors choose when/if they merge Google's commits. The grandparent's comment made WebKit sound like a single entity when it's actually several competing companies with overlapping but also differing views on things. They just happen to be working from a common code base.

Some of Google's engineers have Webkit priveleges. Webkit is a single rendering engine - this should not be confused. It is used by several browsers, who of course, use slightly different compilation configurations, but I doubt that the web designer ever needs to concern themselves with that!

No Alex, not all WebKit browsers have feature parity with each other.

Example please.

Touch events - Android (any version) vs. iPhone (any version).

IndexedDB - Chrome Mobile has it (outdated version), Android and iPhone do not.

Chrome will have Dart support at a later date, no other WebKit vendor is going to implement it.

There are literally dozens, just go to caniuse.com and play around for a bit.

The first 2 are simply version issues, whilst the 3rd is nothing to do with the rendering engine. Chrome uses V8, Safari does not.

Chrome and Safari do differ from each other. But "as they differ from gecko or presto based browsers"? No. Nearly all engine-related bug reports we get apply to all WebKit ports. Gecko and WebKit only rarely have bugs in common.

The "as much" part is BS. Webkit browsers are FAR more alike rendering-wise than they are with any third party engine.

Any difference in rendering between Gecko and WebKit is a bug.

And all software has tons.

No, the two browser have also different levels of implementation compliance with CSS3/CSS4 and other technologies.

So, some of those are not bugs, are differences in features.