I haven't dug deeper due to time availability, but for the same sake of privacy, I've found:

1. `/api/event` endpoint mentioned in the `/stats/script.js` file;

2. There's `/parties/lobby/main/telemetry` in a minified JavaScript chunk asset;

3. There's VitalLens mentioned, and there's an error string in the same asset: "A valid API key or proxy URL is required to use VitalLens. If you signed up recently, please try again in a minute to allow your API key to become active. Otherwise, head to https://www.rouast.com/api to get a free API key."