I tested mullvad browser on
https://www.amiunique.org/fingerprint a long time ago and wasn't impressed, I'll take another look.
Question is what does amiunique.org use in their fingerprinting? If it's using IP as well then you are a unique configuration to that IP and thus 'unique', but otherwise you may well be the same as every other mullvad browser user.
https://mullvad.net/en/browser/mullvad-browser there's some info here about how they combat fingerprinting.
The same browser fingerprint for all Mullvad Browser users
So, in order to be able to hide in the crowd, we give similar fingerprints to all the Mullvad Browser users. But how? Well, let us us give you some examples. We have
standardized configurations and don’t recommend users to change settings.
Firefox’s resist fingerprinting mode is on, and it will spoof many additional parameters and settings that could be used for fingerprinting.
Only a specific set of fonts are made available for the browser and
several hardware APIs are removed – like hardware concurrency and other APIs that could be used to extract information from your device. Another API used to fingerprint you is the WebGL, where the fingerprint attack tells your browser to render a triangle in 3D. The Mullvad Browser
prevents websites from accessing the rendered content by blocking the readPixel function. One more sneaky way to collect your data for fingerprinting, is by measuring exactly how big your browser window is. Just think about it – are you the kind of user that maximizes your browser window? Or are you more a half the size of the screen kind of user?
Letterboxing masks your real dimensions by adding a space around the window. So, no matter how you resize your browser, your window dimensions are unlikely to uniquely identify you. These are just a few of the fingerprint protection actions we implemented with the Mullvad Browser.
Here you can dig deeper into our settings.
It's probably not perfect but better then just basic chrome.