How will torrent trackers check the current number of seeds/liches?

Question

bittorrent

Torrent tracker/forum allows you to download a torrent file, with which you can already download what you need. Often, torrent trackers generally give away other people's torrent files that they found somewhere. And how is the current list of seeds and liches that they show in the interface maintained? I assume there is a way to check it?

Answer 1

The client maintains a connection with the server and reports its statistics to it periodically. Based on these data, the server calculates its statistics.
Clients have the ability to exchange data with each other. This data is not included in the server statistics.
Comparison of BitTorrent trackers .
This is from the front page of torrent+tracker+open+source .