RTCStats.timestamp - fingerprinting and since epoch

[hamishwillee]

The MDN docs for RTCStats.timestamp say this for the value:

A DOMHighResTimeStamp value indicating the time at which the activity described by the statistics in this object was recorded, in milliseconds elapsed since the beginning of January 1, 1970, UTC.

The value should be accurate to within a few milliseconds but may not be entirely precise, either because of hardware or operating system limitations or because of fingerprinting protection in the form of reduced clock precision or accuracy.

Is this correct. Looking at the spec for the timestamp it just says

Timestamps are expressed with DOMHighResTimeStamp [HIGHRES-TIME], and are defined as Performance.timeOrigin + Performance.now() at the time the information is collected.

It isn't clear that this is relative to the Unix epoch (to me) ("milliseconds elapsed since the beginning of January 1, 1970").

I also can't find anything that talks about the accuracy of this value, and how it is affected by fingerprinting.

Can you confirm either point?/the accuracy of the MDN docs?