Full policy: https://tempx.uk/privacy

The Tempx browser extension stores your temporary inbox address, its access token (private inboxes only), and message counts locally in your browser. It requests no access to other websites, browsing history, or tabs, and contains no analytics or advertising code. Message contents are read only on tempx.uk, never inside the extension. Disconnecting removes the saved access; uninstalling removes all data the extension stored on your device. The add-on does not collect, sell, or transfer user data.