What does the timestamp from getStats represent?

I was kind of expecting a unix timestamp here indicating either when the getStats call was made or when the stats were last internally updated/tracked. This does not appear to be a unix timestamp though, so I am wondering what it is relative to?

Unclear whether you mean client or server stats.

Oops sorry about that. I am referring to server stats here.

timestamp field in server stats is set using this:

static uint64_t GetTimeMs()
	return static_cast<uint64_t>(uv_hrtime() / 1000000u);

where uv_hrtime() is defined here:

Returns the current high-resolution real time. This is expressed in nanoseconds. It is relative to an arbitrary time in the past. It is not related to the time of day and therefore not subject to clock drift. The primary use is for measuring performance between intervals.

So, answering your questions, it’s a random value (or better said: it’s an incremental value whose base is random).

Feel free to open an issue in GitHub requesting that such a timestamp should provide the same as Date.now() in JavaScript, this is: “the number of milliseconds elapsed since January 1, 1970 00:00:00 UTC”.