iCloud Passwords lets you securely fill passwords from iCloud Keychain when signing in to websites using Firefox. Any new passwords you create in Firefox are saved to your iCloud Keychain so that they are also available across your Apple devices. The extension can also generate verification codes, which you can set up by right-clicking on a QR code.
TL:DR – The Apple Passwords capability and app was introduced in iOS 18, iPadOS 18, macOS Sequoia, and visionOS 2. A Chrome browser extension followed and now theres a Firefox add-on.
A first release, shows promise
At last Firefox gets an official Apple Passwords add-on. This means that one further part of the puzzle for securely managing passwords can be completed. The iCloud Passwords extension is compatible with macOS Sonoma or later. Unlike its Chrome relative it is not available for Windows.
Android Annoyance
Mostly my annoyance is that I can't use my iCloud passwords on Android. I guess hell may need to freeze over before that happens. Perhaps though the Firefox add-on may be extended to other Firefox platforms than macOS.