other than websites that return a score I argue that websites that return values are not of much value if you do not know how much entropy they carry (eg. are they the same for all the people on the same OS?) or how they are handled in the browser with various mitigations. it’s one thing to read a value, but it’s a whole different thing to understand if and how it can be used, leave alone against a specific tool.

everything is documented on TB’s official gitlab btw, people working on it know their stuff.

Firefox has a bigger userbase than Tor Browser users, and it is a pretty uncontested claim logically. Firefox has Tor Project’s code for anti fingerprinting and per site data isolation upstreamed to Firefox’s private browsing mode since the past 15-20 or so versions now.

Firefox does not have the crowd that Tor Browser has, it does not have the Tor network, RFP is not enabled by default and users will make changes to their settings. even if Firefox has the larger user base there’s no argument for Firefox having a better crowd, sadly there’s no linear correlation in this case.

yes, you can harden it, but the crowd is so small that you will not defeat advanced scripts, nor you should expect to. hardened setups are also not equal as projects like arkenfox and librewolf are going to be tweaked by users post hardening (as they very much should).

applying stylometry analysis

this is opsec and it does not strictly apply to the tool you’re using so I don’t think it’s a valid argument for any of the points explained above.

as for the list you wrote:

• OS Core -> as I said above it can be bypassed even without JS, see TZP and others. that’s why TB has different crowds for different OSes and you just fit in.
• multiple nameserver -> I’m not educated on how the nameserver test works, so I will just shut up on this one.
• resolved and unresolved connections -> traffic analysis does not require JS and using something like uBO or even tracking protection will manipulate your traffic, which is why stock TB does not use any ad blocker. there was a TB issue where LocalCDN was discussed and a dev said it was easy with the proper traffic analysis to detect the extension.
• private mode -> it is detectable but one can just avoid using it even if he has JS on. I’ve never seen it recommended to use always-on incognito so I don’t see the issue.
• tracking protection on or off -> it is off and you cannot enable it in TB (edit: issue).
• browser window size -> rounded values protect the real window size hence you fit in the crowd.
• monitor colour -> iirc it simply doesn’t carry entropy, there were some TB tickets where this was discussed.
• cursor, mouse, last click, caps lock etc -> these are all volatile and fuzzy fping wise. if you can provide a PoC or a paper where these are used to successfully fingerprint a browser then ok, otherwise I don’t see the issue here as well (edit: I found this issue about mouse movement which is 6yo, it’s very low priority apparently and it suggests no JS as only mitigation).
• various estimations and timing -> they are all mitigated, try to run a test and watch TB or Firefox with RFP always return rounded ms values. not to mention Tor circuits provide further protection against everything you mention network wise (edit: in case I’m missing something floating out there I’m ready to stand corrected and I would love a link).

“TB should cover all metrics” (I know you haven’t said it, I just didn’t know how to phrase it better lol) is not a safe assumption: not all metrics are equal, they do not all carry entropy nor they are all valuable fping methods. this brings us back to the initial part of this comment.

the rest of the stuff you discussed, like typing in the wrong tab etc, is mostly opsec and as I said I also value the added peace of mind, but it doesn’t make logins on Tor bad per-se. keyloggers are also a bit out of scope for this discussion imo.

tldr: TB covers enough metrics for most threat models even with JS on - naive scripts swallow the pill, advanced ones are defeated by the crowd, and don’t forget the network -, and the benefits of disabling JS are not that big.

ps thanks for getting back despite the lengthy comments, I added some edits for completeness on both sides of the discussion :-)

I just ran TBB and used deviceinfo.me to verify

ironic how this is posted below an article that says that testing websites are not reliable and that you should not read into the results unless you understand them. I don’t think this is the case, sorry about being painfully honest but I don’t want people to freak out over tests instead of reading a well written article:

• all of the metrics you mention as spoofed (plus a lot more, even ones that you mention in your list like navigator UA, window size, TP on/off, color depth, private mode…) carry close to no entropy. that’s because Tor Browser has a crowd and users fit in that crowd, so even if the script was advanced to go over all the metrics covered by TB (which most of the time isn’t the case), the crowd would allow you to fit in.
• the spoofed UA in the http-header is actually for passive fingerprinting. generally speaking, your actual OS cannot be spoofed and even with JS disabled it can be bypassed by using CSS/fonts. while it’s true that TB safest mode restricts the font list and it will probably defeat most PoC out there (I think? I don’t remember but it should) it’s a big sacrifice in terms of usability when you could simply fit in with the crowd of people using TB on your same OS: arguably that’s good enough for almost everyone.
• timing attacks are mitigated.
• stuff like position in page, last item clicked, cursor position etc is fuzzy, how do you fingerprint based on that? plus https://github.com/arkenfox/TZP#-fingerprints-are-always-loose

You want to know what a JS enabled Tor Browser looks like? A standard Firefox private mode tab with uBlock Origin medium mode and arkenfox user.js applied.

that’s simply not true. TB has further enhancement and code changes, it is based on ESR plus it’s not the same as a private window at all since private mode does not write to disk for example. most importantly tho: TB has crowd and the Tor network, that’s vital and a huge difference. a traffic analysis would also probably identify Firefox + uBO in medium mode vs TB. also, arkenfox does not try to make Firefox turn into TB, that’s clearly stated in the wiki and I would know as I am a repo admin :-)

Can the author explain me why keeping JS on is so helpful

usability, a browser with JS disabled by default is not a good everyday browser for most. the more people use Tor Browser daily and have a good experience with it, the larger the crowd gets.

All the above information I mentioned is trackable for…

I mean once you are subscribed, why would they want to fingerprint you? they already know who you are. when facebook operates as third party it will be isolated plus on a different circuit and with fingerprinting protection, plus (from arkenfox’s wiki):

if a fingerprinting script should run, it would need to be universal or widespread (i.e it uses the exact same canvas, audio and webgl tests among others - most aren’t), shared by a data broker (most aren’t), not be naive (most are) and not be just first party or used solely for bot detection and fraud prevention (most probably are)

I also don’t get what the difference between typing private stuff on facebook on tor or behind a vpn or on your ISP’s network is. however I must say that I still understand why from a “peace of mind” perspective it makes sense to keep stuff isolated, so as I said above mine is not really a strong opinion here.

sorry about typing a lot, but I figured this was valuable information to share, despite being nothing new.

I will start by saying that the author of the article was a tor researcher and dev so this gives some context on the content and me posting this.

which is a very risky thing to do for someone not familiar

may I ask why? I generally agree with the sentiment of the article but I don’t have a very strong opinion on this and maybe I’m missing something.

PS I don’t think the usual “I will end up in a list of people who use Tor” argument is a valid one.

Preferring JavaScript stay disabled is a better choice, the next best is only allowing JavaScript when needed momentarily.

I disagree with this, it’s simply overkill for 99% of the people with arguably no benefit at all. what’s there to gain?

You should certainly export your passwords from Bitwarden so they can’t keep them hostage.

imo your tone is a bit blowing this out of proportion, you can stay on the free tier, pay regularly for a very good service or even self-host. they are not keeping your password “hostage”.

Only the last two categories are impacted by using an adblocker, in fact they are probably the less important ones.