Math routines are OS fingerprintable
The Math class now exposes high-precision versions of several mathematical functions. If these are OS-specific, they may be fingerprintable.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math
OS-level fingerprinting probably is not a terribly high priority. The only situation where this is high priority is if different OS versions and library versions end up producing different results for these functions.