>In the meantime, Vivaldi added good old, classic RSS reader (and email client)

I still dont understand why RSS isn't part of every browser. In the old days we have problem with syncing. Today most browser bookmark has online backup. You have a bunch of RSS links, that could be saved as Bookmarks / Favourite. The content are simply XML and all inks are synced to all Browsers. You laid them out like in Feedly and that is it.

I could understand email being a lot more difficult, but RSS? Am I missing something?