@luetage Agreed with the js mod. However, I think worrying over something we can already do "is dangerous" -- while some power user are already doing it make this issue pretty pointless. Instead of leaving it as of such, I think the proper way is provide a user friendly & safe method for mod support, be it extension, CSS, or Js. The most important thing is all Js mod must be open source, allow public observation, & access to the source code like what we are already doing in the mod forum.
That's why Firefox & Chrome have their own extension store, so that the masses won't go to unsafe/unofficial places looking for mod. But I doubt Vivaldi will be able to maintain a store like that... it's too much fuss & difficult to monitor all the mod over time.