What linking sends

Linking a server sends zrs.dev its hostname, its ZRS version and a license request.

The license request includes details about the server's hardware, which zrs.dev uses to verify the license. The server signs the request, and the hardware details in it are encrypted so only zrs.dev can read them.

zrs.dev never stores the hardware details or the request. It keeps a keyed hash of the details, enough to recognise the same server later, along with the server's hostname and ZRS version, when it last contacted zrs.dev, and the licenses issued to it.

Deleting your account deletes its servers, their hashes and the licenses issued to them. zrs.dev keeps a record that the license existed, marked ended and with no account on it.