Mozilla will begin protecting users’ saved passwords with a master password with the release of Firefox 76 later this year. It's is already part of the latest Nightly builds but most users will begin using the feature from May 5 if the company sticks to its existing release schedule. With more people accessing sensitive services such as bank accounts online, this move makes sense.
As it stands right now, if you leave your computer unlocked, anyone with access to your computer can head to the hamburger menu > Login and Passwords and then start scrolling through your accounts and passwords. Optionally, you can set a master password to add more security but many users do not do this, especially less technical users who don’t even realise that they can set a master password.
The new feature will be available on Windows and macOS. If you’ve not set a master password within Firefox, you’ll be prompted to enter your operating system’s password instead. If you prefer to use biometric authentication, such as a fingerprint, you can use this also. Unfortunately, Linux users do not yet have access to this feature and its unclear whether it will ever be implemented on that platform.
Once you’ve entered your operating system password, you’ll be able to access your saved login information for five minutes before you are asked to re-authenticate yourself.
Source: Sören Hentzschel