What it uses:
- Your ClassCharts login session. While you use the ClassCharts parent website, the extension reads the login header the site already sends, so it can fetch more than one day of your child's timetable.
- Your child's timetable (lessons, teachers, rooms and times), fetched directly from classcharts.com.

Where your data goes:
- Only to classcharts.com. The extension has no server of its own, no analytics and no advertising. Nothing is sent to the developer or any third party.
- The login session is kept in the browser's session storage and is cleared when you close the browser.
- Your settings and any names you type (titles, week names, short subject names) are saved locally in your browser and deleted if you uninstall the extension.

The extension only reads timetable data. It never changes anything in your ClassCharts account and does not run on any other website.

Full policy: https://github.com/skeffling/timetable-plus/blob/main/PRIVACY.md