Browser Profile Router does not collect, transmit or share any data. It makes no network requests, has no analytics or telemetry, and everything it handles stays on your computer.

WHAT THE ADD-ON READS

- Your mail accounts and their identity email addresses, to decide which browser profile belongs to which account.
- The message you are viewing or have selected (its folder, account and recipient addresses), to determine which account a clicked link belongs to. Message bodies are not read, except that a script in the message view watches for clicks on http/https links to get the link's address.

DATA EXCHANGED WITH THE NATIVE APPLICATION

The add-on uses native messaging to talk to a helper program (profile_router_host.py) that you install yourself. The helper runs locally and is needed because add-ons cannot launch other programs.

Sent from the add-on to the helper:
- The address (URL) of a link you clicked, so the helper can open it.
- The browser and profile identifiers to open it with (for example "chrome-canary" and "Profile 2").
- The same browser and profile identifiers whenever the selected message's target changes (see "Data stored on your computer").

Sent from the helper to the add-on:
- The list of installed browsers and their profiles, including each profile's display name and, for Chromium-based browsers, the email address of the account signed in to that profile. The helper reads this from the browsers' own local configuration files. It is used to fill the options page and to match profiles to your mail accounts automatically.

Your mail account addresses, message contents and message metadata are never sent to the helper.

DATA STORED ON YOUR COMPUTER

- Add-on settings (which account maps to which browser profile) are kept in Thunderbird's extension storage.
- The current target (browser and profile identifiers only) is written by the helper to $XDG_RUNTIME_DIR/browser-profile-router/context.json, a per-user directory that is cleared when you log out (or to ~/.cache/browser-profile-router/ if XDG_RUNTIME_DIR is not set). It is read by the optional link handler (thunderbird_url_handler.py) for links opened by other add-ons.

REMOVING YOUR DATA

Uninstalling the add-on removes its settings. To remove the helper, delete browser_profile_router.json from your native messaging hosts directory, run host/register_handler.py --uninstall with Thunderbird closed, and delete the repository.