I don't think this is a good idea. Websides have the ability to detect Firefox and other browsers is in light or dark theme. They should provide themes by themselves. Make a built-in dark reader alternative also break the rules. More and more website...
If Mozilla made a native dark mode support, browsing some websites which already support dark mode such as GitHub may meet some problems. I'm not a developer and I don't know there are APIs or not to let the browser know that specific websites have d...
I think tab grouping is not necessary as there is a multi-windows support in Firefox desktop. Google Chrome supports both tab groups and rename window, make a duplicate in functions.
