Still no hope that this would ever be made into a WebExtension, unfortunately. The API won’t be allowed to access PWDs and that’s that. 
We can use all sorts of programs and scripts to read (and decode, print) the password database, but it can never be managed; this, seriously, blows.
I’m not sure WHAT Mozilla is thinking, same with (Google) Chrome and all of the other browsers. Like, why would we want to entrust our logins to some (online) 3rd party software… Applications that are available for FREE. There are dozens, like LastPass and whatever; and why are they freely available (srsly, any1 know)?
Anyway, perhaps someone is bothered to let us know what they’re using for management? The browser itself and then, just, manually copying-over the key4.db and logins.json files when needed?
(Profiles - Where Firefox stores your […], https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data)
P.S.
Looking for something “cool”, because even when using the simplest of tools like PasswordFox (https://www.nirsoft.net/utils/passwordfox.html), the Master Password has to be removed first, in order for it to gain access to the -otherwise encrypted- PWDs. There’s always some pain associated with whatever software method. :f
In another recent reply (that I made), I found these nutcases (?..:)) making a 70MB setup file to grab the passwords, ff-password-exporter (https://github.com/kspearrin/ff-password-exporter) and I’m having a hard time grasping WHY (rly, no comprendo).
EDIT: Though, I suppose that a (3rd-party) password vault can actually be (much?) more secure than the built-in password mechanism?..