No OSX Service Menu is not enabled
Just a quick: The Service Menu is not enabled in the Interface, this means you cannot interact with the OSX Service scripts. It should be under Vivaldi in the dropdown. That is not good. I have to open all Webpages where I want to do some stuff (like saving code to file or running it directly, whatever) in another Browser. This should affect a lot of power users. Which is your target group, I guess. Hey, your Browser is now easily as stable as the Stuff other people release as finals.
The macOS's service menu is very important for many users, not only for power users.
It is easy work to add a service menu to hand over texts to other applications.
I strongly hope designers vivaldi decide to add it soon.
Chances a developer will read this are small. Then again they are probably aware of it.