See prism-break/prism-break#1862 (comment) (although note that I'm not filing this with my PRISM Break contributor hat on). From the README it seems like this extension only changes the UA; is that correct? If so it may be doing more harm than good because by changing the UA but not the APIs exposed in the browser (which would let trackers determine the "real" browser version anyway), this extension may actually be making users more uniquely fingerprintable, not less.