Only changes the tab icon not the favicon for bookmarks.

did not work on firefox103

Не работает.

This is a very sad review. I cannot recommend this add-on because I can find no easy way to actually use it! The developer doesn't give any instructions, which lacks courtesy and consideration and handicaps his chances of getting anyone to use the thing! Advice by other reviewers who also found no instructions are opaque or technically impenetrable. A good piece of software should either have foolproof instructions provided or be so "bleeding obvious" (Monty Python quote!) that none are needed. This one has neither and consequently must be considered as badly designed for use by anyone other than the guy who wrote it.

Not sure why it's even listed. Seems very clunnky to have to go to options each time to use. Never been able to save or use. It does not seem to work anymore. REMOVE.

Does not work anymore. Used to work fine a couple of years ago. I dont get why people are giving it 5 stars today. Are they on a really old version of Firefox perhaps?

I could not get this app to work. I couldn't see the extension icon in the top-right of firefox, so there was nothing to click to get the favicon changed. Frustrating.

Used to work but no longer works.

Could not get it to work, I tried restarting Firefox, and removing all history entries for the site.

Does Not work at all. Tried refreshing, changing urls etc.

Unfortunately did not work. I tried several times to customize a Gmail URL to show only starred items in my inbox with a star icon, but it kept overwriting it with the regular Gmail envelope icon. Disappointing.

great idea but simply does not work

There are no instructions. I thought you would right-click on a bookmark to change the favicon. Instead, you need to first open the favicon-customizer add-on. Near the bottom right of the page, there is an area you use to type in the webpage name and link a favicon. Took me a while to find this. I've tried to make the add-on work but so far I can't make it work in Firefox 60.0

Hubiera sido buena si me hubiera funcionado. Tengo Firefox 59.0.2 x64 en Windows 7 x64.
Adjunto video donde se puede ver que no cambia el icono ni el título de la página.
https://drive.google.com/open?id=1hRCwR7VxfMriIKP29_9d3FAwRcuOFkoT

¿Se podrá corregir?
Gracias!
----- 29/11/2018
Intentando nuevamente con la versión de Firefox 63.0.3 (64-bit) y aún no funciona del todo. Sólo cambia el icono si es que no hay "Nombre" ni "Título de página", pero sólo dura un momento, luego se pone el icono original del sitio web. Además, no se puede cambiar el título de la página.
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It doesn't work for Firefox 57 Quantum. there are no instructions anywhere for how it should work.

How to use? Cant see anything new in my Firefox.