Apparently my CSS font list alone can uniquely identify my browser out of those tested so far, which is rather concerning... Is there some Firefox extension I

Apparently my CSS font list alone can uniquely identify my browser out of those tested so far, which is rather concerning... Is there some Firefox extension I can use to spoof my font list to some subset of my existing font list to conform with some widely used system default? I do have some custom fonts installed, but I'd prefer random websites I visit to not know about them if possible. Also, the way plugins are handled in Firefox has always bothered me quite a bit. I can disable them, but not remove them. What gives?