Random person, random planet, random OS tinkerer.
Yeah. I thought about that. When you add an icon to your rows of shortcuts in Firefox and it fails to fetch the correct icon and gives it a generic letter instead and you want to add an icon yourself you cannot just upload or insert an icon to your Firefox, you will need to point it to some web link where the remote icon is. I can imagine Firefox wants to check at each startup whether the remote icon has changed or not (Not completely unreasonable. Think about Twitter changing to X).
That is pretty cool for folks that want a quick and easy way to block ads.