Teams Phone Fix is a Firefox add-on designed to resolve a common issue for Linux users attempting to use Microsoft Teams for phone calls. This add-on addresses the error message indicating that the browser is unsupported for making calls. It works primarily for Linux users, but may also function on Windows and MacOS, although compatibility is not guaranteed. The extension modifies the browser's user agent to mimic Microsoft Edge or other supported browsers, allowing users to bypass restrictions and use Teams seamlessly.

The add-on operates in the background without requiring user interaction. It does not collect personal data, only modifying the user agent when necessary. Users can customize their user agent settings, which are stored locally. To ensure proper functionality, users must reload the Teams tab after installation. Additionally, the extension requires permissions to access tabs and store settings, aligning with Mozilla's privacy standards.