I got an issue on Github that the icon of my node is not appearing on flows.nodered.org:
If found out that this is the case for all my nodes that use a FontAwesome icon, like this:
... outputs: 1, icon: "font-awesome/fa-calculator", paletteLabel: 'calc',
The icon appears correctly in the flow editor:
Not sure what is wrong with the generated html on the flows site:
I assume that is an esthetical, low-priority 'hidden feature'...