Mozilla VPN is a paid subscription product that encrypts your full device’s traffic. This is a true VPN in the traditional sense of the technology. The Built-in VPN provides you with 50 GB of free browser-only protection for your IP address. This is an industry standard way to provide additional privacy protection to users at low to no cost and an important tool in an everyday user’s toolbox to keep internet lurkers from knowing where they’re connecting from.

More information.

https://support.mozilla.org/en-US/kb/built-in-vpn https://blog.mozilla.org/en/firefox/built-in-vpn/ https://blog.mozilla.org/en/firefox/firefox-148-149-new-features/

This "VPN in Firefox" feature is experimental and is being introduced to the Firefox user base through a progressive rollout starting in Fx 149.0. It may not yet be available to all users.

Users will have 50 gigabytes of data monthly in the U.S., France, Germany and U.K. to start. Available in Firefox 149 starting March 24.

In the KB article

To use VPN, you need to sign in with a Mozilla account. If you’re eligible, you’ll see a prompt in the Firefox toolbar inviting you to set up the feature.