I have read quite often that addons should not be installed on tor browser but I have I guess a two teired question regarding that. Is if possible for adversaries to fingerpring ones addons if scripts are turned off? If so, or even if not but perhaps I turn scripts on occasionally, or maybe can make make-life-difficult-for-adversaries reading whonixVM, how much am I compromising myself using addons? I ask because while having javascript turned off conviently does get rid of alot fo adverts etc it doesn’t get rid of all, and I would like to use a page reformater, and a few other things to make reading more, enjoyable. Pitfalls?
The best way to find out is to test it first before you do anything dangerous in your situation/location.
Go to one of the following websites and run tests with and without Javascript on and see what the reports show:
(There are many others, but you will quickly discover your needed information via the above three).
From previous testing, I suspect that even the presence of additional add-ons will show up, but without Javascript enabled a lot of additional information that might be leaked will show null results.
On the basis that the boilerplate advice from Tor devs is NOT to change the add-ons selection from the default HTTPS Everywhere and No Script ones, then it is safest to assume that the (likely) detection of further add-ons will make you very fingerprintable (unique) and thus traceable across the militarized net.
How badly do you want or need them? The majority of activities can be achieved in Tor Browser with the default configuration and (often) no Javascript.