I've been around 2 hours trying to pass my firefox passwords to Opera data
Well I finally manage to have my sites in lastpass and keepass....
What do I now, because when I am in Opera just says import from browsers but firefox just says html...
To fill more on detail about Browser vs. Extension topic. The browsers will not sync custom data if it is not available naturally. In your case, if the extensions need to be added to Opera and imported through extension settings. I would assume that the HTML file that is generated is going to be used as import key to your plugins.