This app requires no account or login. It contains no ads, no analytics SDK, and no third-party tracking. To download lessons and understand app usage, the app contacts our content server with a randomly generated installation identifier. The server records the installation identifier, IP address, country derived from the IP address, platform (iOS or Android), operating system version, phone brand and model, app version, first and last used times, and request count. This data is used for content delivery, access recognition, operations, and usage statistics. It is not used for cross-app tracking and is never sold or shared. The installation identifier is not a name, email address, or account. Your learning progress, answer history, and settings stay on your device and are never uploaded. Deleting the app deletes them. The server uses HTTPS and HMAC signing. It does not keep access logs for ordinary users (the application layer still records the usage data described above) and does not use advertising identifiers. Usage data is retained for 90 days and automatically deleted when an installation has not been seen again. Access grants are retained until revoked. There are currently no ads. If ads or paid features are added later, this policy and the store privacy labels will be updated first. Contact: [email protected]