Compatibility 
Works with: Firefox 8.0+
Background
The new default favicon for sites that don’t have a favicon is nothing more than a dotted square. In the past it resembled a piece of paper.
The Tweak
Add these lines to your userChrome.css in the chrome folder within your profile folder [directions]
Firefox Logo (
) - rob64rock has a stylish script that will do this as well.
/* Fx branding tab Favicon on New/Blank tabs */
tab .tab-icon-image:not([src]) {
list-style-image: url(“chrome://branding/content/icon16.png”) !important;
}
#urlbar #page-proxy-favicon:not([src]) {
list-style-image: url(“chrome://branding/content/icon16.png”) !important;
}
menuitem[class="menuitem-iconic bookmark-item menuitem-with-favicon"]:not([src]) {
list-style-image: url(“chrome://branding/content/icon16.png”) !important;
}
Other Logo (
)
/*Replaces the ‘new’ default Favicon */
tab .tab-icon-image:not([src]) {
list-style-image: url(“chrome://global/skin/icons/folder-item.png”) !important;
}
#urlbar #page-proxy-favicon:not([src]) {
list-style-image: url(“chrome://global/skin/icons/folder-item.png”) !important;
}
menuitem[class="menuitem-iconic bookmark-item menuitem-with-favicon"]:not([src]) {
list-style-image: url(“chrome://global/skin/icons/folder-item.png”) !important;
}
Notes
- This change took place in Firefox 8.0
Updated: November 15, 2025
