A good idea and a useful tool, Didier, thankyou!
I have only rated it a 3 star because since the Firefox upgrades (I am on version 60.1 currently as of August/4/2018) because its not always working with a lot of websites; and also because it has been well over a year since you last updated!
NOTE:
To all of the people past, present and future who use this add-on...
From what I have read in the comments, and the lack of any replys from Didier, I IMHO think that the author ...
1) Can't be bothered to interact...for any number of reasons
2) Has lost interest in keeping it updated (possibly due to Firefox updating so often etc.)
3) The author is having health problems and can't continue working on this add-on
4) The author could have died (a point a great many people don't even think of)

very good

Love this add on, works great!!!

This works fine only I'd like a single icon in the toolbar to toggle showing passwords. Having show/hide next to each password field is kind of useless. Obviously if you can't read it you need to show it.

Other than my own personal opinion, very useful.

عدم تجربه کافی

Simple & Useful <3

Needs an update, does not work well at all sites especially when the website brings out another window on top of the current web page.

Great, but option to see password by default would be a welcome bonus.

I sit alone in my home office and NEVER need to hide a password. I enjoy this capability, but I wish it allowed me to default to Show. It would save me a click at each login.

It doesn't work with most of italian sites I usually navigate.

Mamtap

THIS ADD ON GIVES ME SECURITY WITH MY PASSWORDS

very nice