I found that the local time can be obtained on some Avatars and displayed on the UI. How is this implemented? Isn't C# allowed?

That would answer my question

On avatars, it can be done with parameters reading data from a program using OSC.

Thank

If I’m showing you my time, it’s OSC parameter.

But if I’m showing you your time, i think it’s worth pointing out for audio link worlds one of the data passed to the shader is the local time.

Lacking both audio link and OSC, shaders can know how long player has been in instance.