Which means among other things that they didn't have the capacity to sustain manifest v2 while Google pushed the browser into v3. And some version of that will be true when Google starts pushing, say, mandatory sign in, or AI powered DRM enforcement, or hard coded browser level warnings to comply with the law if you visit Anna's Archive, or limit your search engines to "safe" search providers from a list provided by Google, or using your location to determine if you're in a jurisdiction that has banned certain xxx sites.
Love the team, but the world isn't fair. They are the example I keep coming back to whenever I hear people say "Mozilla should focus on the browser!" (as if they don't). Opera is your perfect natural experiment in demonstrating that success is driven much more by distribution monopolies. If focusing on the browser and delivering best in class performance and focusing on core features your users most wanted were the things that delivered market share we would all be using Opera right now and they never would have had to sell.
No but they did build an ad-blocker right into the browser so the main reason people were against the change doesn't really matter any more.
They had lots of cool featues built in:
IRC Client
Email Client
RSS Reader
Note taking (I used it a lot)
Gestures (those were awesome, I fondly remember holding left then right click and the other way around to move back and forward, but these proved to be a sign of Operas decline, some bugs with them were never fixed while we kept getting newe releases, (remember the potato ad?))
Sharing local files as a website right from your browser
They invented tabs
They might have had torrent support too, don't remember clearly.
It was fast even with all this.
Vivaldi's UI is built in JS, it feels slow, all my clicks are slow. I never got myself to using it more than a few minutes.