This extension does not integrate with Firefox's password manager - it replaces it.

I expected access to my Apple Passwords from within Firefox's existing password management workflow. Instead, I ended up with Apple's password manager grafted onto Firefox.

The extension may be useful for users who want to abandon Firefox's password manager entirely, but it is not a true integration with Firefox.

There is also no synchronization between Firefox Password Manager and Apple Passwords. Not that I personally wanted that feature, but users expecting seamless integration should be aware of this limitation.

Ironically, the experiences with APM was actually better for me in Firefox than it is in Safari.
Disappointing.