Thanks!This was added before any standardization to meet aggressive EU deadlines, so there’s not really much besides Apple’s current documentation on it. I do not believe extensibility is defined (eg there may be limits supplying points of interest and the like).
Really weird, not even Siri requests are intercepted with the custom geo-navigation:// url scheme Apple state you need to support. I'd thought that all Apple internal requests to Apple Maps were routed via this scheme