The only exception is that we monitor some requests with the IP address that you are currently using, so that we are able to detect malicious use or system defects. All of these fields are alpha-numeric, with almost no relation to your real identity. A security identifier (csrf) is also stored to prevent a particular type of online attack. It contains a session ID - a unique, anonymous user ID combined with an authentication identifier (user_data).
A so-called cookie stores identifiers that make it possible to respond to your individual requests. Some data is technically necessary to be able to visit the page at all.