How to force Quantum to use a custom icon for all .url links

[Amby19]

I've already changed the Firefox Quantum desktop icon for the application itself. But I also want to change ALL the icons created automatically, including those used when creating new .URL desktop icons -and- the icon that shows up in the taskbar when Quantum is running. I need this for both Windows 7 and Windows 10.

I've seen a great many posts on how to manually change icons after they've been created, but that's not what I want.

One reason I want to be able to do this is because I still have a pre-Quantum version of Firefox installed (with it's own profile), which I'll want to use occasionally because there are a few times when I want to use some old addons. But Quantum Firefox creates exactly the same icons as the old Firefox, which I dislike.

Is there a way to do this? I'm a knowledgeable user, so don't worry if the process is complex.

Thanks!

[morat]

You can set the browser.shell.shortcutFavicons preference to false to disable shortcut favicons.

You cannot set a custom value for the IconFile field. The logic is hardcoded in the nsDataObj.cpp file.

Url file format
http://www.lyberty.com/encyc/articles/t ... guide.html

Reference
http://dxr.mozilla.org/mozilla-release/ ... utFavicons

[Amby19]

Ok, thanks, morat!