It is really a pity that there are so many browser extensions who get this right, but the browsers themselves don't.

That's why it is so refreshing to see at least one of them (Firefox) actually trying to get it right.

The technical term for a browser is "User Agent". That naming may be historic and old-fashioned, but it was named that way for a reason. It's time to restore the original meaning, to make the browser an agent who actually acts on behalf of and in the interests of the user, not the website creator.