https://addons.mozilla.org/en-US/firefox/addon/uacontrol/
https://addons.mozilla.org/en-us/firefox/addon/user-agent-js...
String...
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:42.0) Gecko/20100101 Firefox/42.0
Update the string every now and then?
https://techblog.willshouse.com/2012/01/03/most-common-user-...
Disable all plugins.
Best I got, sorry.
Is there a way to pretend plugins are disabled when they're on click to play?
Also, being able to toggle the UA and setup lists to dynamically set it is helpful in my usecase.
Of course, you'd actually have to do a bit more work to make it bulletproof (otherwise fingerprinters could use the fact that you modified your default navigator object as a way to uniquely identify you !)
I imagine ultimately it's almost impossible to defeat fingerprinters in JS, as they could do tricky stuff like timing attacks to get you.
Use NoScript if you're concerned.