Listudy uses a cookie to remember that you are logged in. The cookie stores (encrypted) that you are logged in, what your username is and when the cookie expires.
Account creation:Username, hash of the password, creation date
Study creation:The PGN, the supplied title, orientation and description.
Save study progress:A json object with the progress of the learning (a score for each of the moves based on how well the performance on the move is)
Favoriting Studies:It is stored what study you favorited. This is public information and displayed on your profile page
When you visit the site some information about the request is logged on the server. This information is the time of the request, HTTP method, the URI of the request, the status code generated by the server and the referer of the request.