On the site where it shows that there are XX active players in a game for example, what does this actually mean.

I believe its how many runners have submitted a run in the last X days but i might be wrong

Afaik it considers you an active player if you have submitted a run in the last 30 days.

Actually I believe being active is a linear function. So if you submitted a run today, you count as one active person. If you submitted it yesterday, you count as like 0.97 active people. This goes down day by day until you haven't submitted a run for 30 days, at which point you no longer contribute to the active player count.

You are right, but after some calculations I believe the "active counter" goes linearly from 1 to 0 after 50 days, not 30. So each player contribute to the active players counter by the relative score of their last submitted run. This counter is rounded up, and the final number is what shown in the statistics page for the game. If you hover on the number of the active players, a tooltip will appear which shows the decimal number without the rounding.

Interesting.

Ok so it looks like there's 2 versions of active player count

So using Minecraft Java Edition for example

This one which can be found on the game statistics page looks like it's calculated from the method above https://drive.google.com/file/d/1X-J1h_ALKA8E6T3URHhx4bAY7gmP2j-G/view?usp=sharing

And there's also this player count found on the games page which looks like it's just from the amount of submitted runs from players in the last 50 days https://drive.google.com/file/d/1zawtXT8RvpkXYLLekyB1Hxd_2D6FRq2k/view?usp=sharing