This seems to be a bit of a miscommunication. But an extension is not native. And all versions of Ubo are extensions, something else doesnt exist.
You can define native a few different ways in english language so i get how it might be confusing if its not your first, but its similar to how a mod for a game is not native to the game.
When you mentioned “native adblock in chromium” That does exists and it requires no extension. But they are never as fully featured as the full Ubo extension which only works on firefox. Which is what this comparison is about.
I hope that helps.