Does it really provide that much entropy? Maybe back in the days when browsers didn’t auto-update, but intuitively it should only provide about four bits at most (os: Android iOS macOS windows, browser: chrome safari edge ie ff) except for a few rare users who don’t stay up to date or choose a weird browser (and those folks probably are a little confused about how privacy works).

ohhhhh you betcha.

https://amiunique.org/

i ran this on my work laptop (windows 10 / firefox - mostly default settings). the "details" tab shows a full breakdown of each fingerprinting component with a "similarity ratio" (percentage of fingerprints that share the same value).

every entry is 20% or greater, most of them around 50% except for timezone (4%), canvas (1%), and user agent (0.12%).

so, yeah, user agents are still the largest source of entropy by a wide margin for fingerprinting scripts.

I suspect this is just stale data. I can’t think why the most recent version of a browser would put me at one in a thousand.