[halicarnassus]

Many extensions need full access to the DOM, because their functionality depends on it. Their sole purpose is to manipulate the DOM for various purposes.

That's why it is always a risk to use browser extensions and you really have to trust the people behind the extension.

Obviously, if the browser supports it, the access should be limited to the sites where it actually matters. Like a YouTube ad blocker to youtube.com. Unless you make a living from YouTube. Then you don't want to block ads for ethical reasons as well as security reasons, because it can kill your livelihood.