"Crash Reporting, Metrics,"

These are not proprietary, actually.

" Audio & Video Codecs,"

Neither is this, last i looked (but i haven't looked in a while).

The "proprietary" codec support is open source but disabled by default in a Chromium build unless you pass proprietary_codecs=1. Why? Patents. AFAIK, Google pays for a license from the patent holders to decode the codecs within Chrome, but not an open-ended license for anyone using the source code. This is not their fault and no different from how many Linux distros don't include MP3 decoding by default. (Incidentally, the last MP3 patent is set to expire at the end of this year…)

The last MP3 patent already expired a week ago actually.

Yup. Our only closed source bits at this point are Flash and the Widevine CDM (DRM), both of which can be disabled from: Settings -> Content Settings.

Better than Edge that is fully closed source.

You can use Chromium directly if you want to.

Many important projects exist because Chromium and v8 are open source.

Actually the JavaScript engine of Edge is open source.

Chakra is open source. The rest is not.

The IE/Edge layout engine has always been a source of infamous trickery. It would be good that they finally open source it.

As Chakra is part of Edge, then Edge is not fully closed source.

Edge is closed source. You have no way of verifying the build of Chakra used is the same as the open source version. Well it might be possible to reproduce a build of Chakra to do a binary comparison but i am not aware of anyone doing it.

There's nothing stopping you from compiling https://github.com/Microsoft/ChakraCore and checking if Chakra.dll matches that which is distributed with Edge.

AFICT you cannot build a like-for-like chakra.dll from ChakraCore due to https://github.com/Microsoft/ChakraCore#using-chakracore

The chakra.dll that comes as part of Windows/Edge includes the additional parts not included with ChakraCore (at least that is how it reads to me).

And not to mention: DRM.

No thanks.