Anonymous identity
The server assigns an opaque random visitor identifier and a shorter-lived session identifier in first-party HttpOnly cookies. They let the site keep one anonymous visitor's saved settings, repertoires and training state separate from another visitor's data. They are not a name, email address or account.
Usage analytics
The server records basic request and usage information so the site owner can understand traffic and improve the application. This can include the visitor/session identifiers, current and recent IP addresses, browser user-agent, referring page, requested route, language, viewport/screen size, session duration, campaign parameters, and coarse network location supplied by the hosting edge such as country, region, city, timezone and data-center code when available. Common crawler/bot user agents are classified separately from human traffic.
Chess Trainer does not use canvas, font, hardware or similar browser fingerprinting to create an additional identity.
Your chess data
Anonymous visitors receive separate server-side storage for personal settings, repertoire state, saved positions and training progress. A visitor does not need to sign in to use that storage.
Feedback
If you explicitly send feedback, its description is stored on the Chess Trainer server for the site owner to review. A screenshot and technical context are stored only when you choose to include them. Administrative feedback tools and whole-application backups are not available to ordinary visitors.