signons2.txt stores saved user names and passwords. It also stores a list of sites for which passwords are never saved. The Options/Preferences dialog contains a UI to view and remove the passwords. This file is encrypted to help prevent others with access to your computer from seeing your passwords.
Due to a fix for bug 360493, signons.txt was replaced by signons2.txt starting in Firefox 184.108.40.206 and Firefox 220.127.116.11.
Manually editing signons2.txt is not recommended because its contents are encrypted and there is a UI to do common tasks.
The file's contents are as follows:
#2d (list of domains for which passwords are never saved) . (site with a saved password) (name of HTML user name field or blank for HTTP authentication) (encrypted user name) *(name of HTML password field or blank for HTTP authentication) (encrypted password) (the domain of the log in form) . (more entries like the one above)
This file can be moved to a different profile as long as it is moved with key3.db, which is the encryption key.
Deleting signons2.txt will delete your saved user names, passwords, and "never save" password settings. If you have a signons.txt file, it will be migrated into a new signons2.txt file; otherwise, a new signons2.txt file will be created when needed.