When I drag the “Website” resource from the System category and put the URI in the URL with “Access in background” checked, nothing happens.
When I remove the checkbox, windows prompts me to find app in the store that can open such kind of link. Obviously there is no such app, so I wonder what is the hack here.
I don’t see any option in Syrinscape offline players to register them as handles for such kind of resources. There is no option in the Settings app to register such thing manually and should be done by the application programmatically using Windows API which I am not familiar with. Starting the player in Admin mode also does not help.