Essentially, it is the client’s best guess of what
os.clockwould return on the server.
It is not at all an estimate based on what
os.clock() would return on the server,
os.clock() has no Unix epoch baseline. The single function it could be said to estimate the server value of would be
tick() is not monotonically increasing and
This distinction is important, any code relying on that documentation will almost certainly be incorrect.
Documentation says nothing about whether
DateTime.now() is monotonically increasing.
Workspace:GetServerTimeNow() is, so it’s unclear.