So, Google Chrome gives all *.google.com sites full access to system / tab CPU usage, GPU usage, and memory usage. It also gives access to detailed processor information, and provides a logging backchannel. This API is not exposed to other sites - only to *.google.com.

This is interesting because it is a clear violation of the idea that browser vendors should not give preference to their websites over anyone elses. The DMA codifies this idea into law: browser vendors, as gatekeepers of the internet, must give the same capabilities to everyone.

Depending on how you interpret the DMA, this additional exposure of information only to Google properties may be considered a violation of the DMA. Take for example Zoom - they are now at a disadvantage because they can not provide the same CPU debugging feature as Google Meet.

For those interested: this is done through a built-in Chrome extension that can not be disabled, and does not show up in the extensions panel. Source code is here: https://source.chromium.org/chromium/chromium/src/+/main:chrome/browser/resources/hangout_services/… It is unclear whether the same extension also ships in other Chromium derived browsers.

Update: in Microsoft Edge this capability is also available exclusively to *.google.com domains

And for everyone that keeps saying "Use Brave!!!": Brave also has the same behaviour as Chrome and Edge here. The extension that allows Google to retrieve this information exclusively from *.google.com is also pre-installed in Brave.