Publicly-disclosed UXSS flaw was exploited against Opera users for over 2 years

Any referred domain had full access to the referring domain (even across multiple redirects).

This means badsite.example can have access to your Google account just from clicking on a Google search result. I made an exploit that worked on Twitter and Reddit to retweet/upvote/etc.

Correct. I wanted to include that, but I couldn't fit it in the 80 character title limit.