With more context it makes sense. It isn’t just smartphone batteries, but lots of consumer electronics. Phones, tablets, cameras, ebikes/scooters/cars. And other parts of the legislation are focused on battery recycling targets for long-term sustainability.

From another article on the resolution:

All electric vehicle and rechargeable industrial batteries above 2kWh will need to have a compulsory carbon footprint declaration, label, and digital passport.

The parliament also passed new targets for collecting waste and recovering materials from old batteries.

They’re targeting batteries (first) because they use so much lithium and other relatively rare metals, and having so many batteries up in landfills is not only terrible pollution when they leech into water and stuff, but it’s just not compatible with our current and foreseeable dependence on lithium battery tech.

As other comments have pointed out, Firefox doesn’t necessarily support the necessary APIs that Discord is using for this. I have the same issue where neither Firefox don’t support the in-browser MIDI API, so I need to have Chrom(ium) for a webapp that lets me configure some MIDI hardware that the manufacturer provides zero computer interface for.

I’d like to use Firefox for everything, but there will always be some edge cases like this as long as there are APIs or other features that it doesn’t yet support. Of course not to say that securely implementing every new API is trivial, but that’s just how it is right now

mostly cuz EU gives rights and protections to consumers, not corporations

might be that most of us are just lurking 👀