PasswordFox makes use of the Firefox library nss3.dll to decrypt the stored passwords. When you launch this tool, it detects your default Firefox profile and decrypts the passwords stored there for you. You can see the usernames, passwords, website URLs and more on the list. It even shows you the password strength for each of the decrypted passwords.
If the stored credentials are protected by a master password, then you can click on the open button in the toolbar and enter a master password for the profile. In the open folder dialog, you can also specify a custom Firefox profile folder. This profile folder could be from a previous backup, a portable version of Firefox or an obsolete profile of Firefox that you do not use anymore.
If the password decryption library included with Firefox browser is not able to decrypt the passwords, perhaps due to a change in the library code across various versions of Firefox browser, then you can also specify a particular version of Firefox installation in this tool.
You can also export the list of Firefox credentials to a text file, HTML file, CSV file, XML file and more. The password files saved in this way contain everything someone would need to login to various online services or websites, so you should be careful when saving or storing such files on your local storage disks.
You can download PasswordFox from https://goo.gl/vjkv4v.