Just a simple link so when viewing a POI on Maps, you can click and view the same POI immediately on Google Maps or other map providers.
The main reason being if more information is needed, such as full reviews, it is quick and easy to get to. Currently there is a link to get directions from other maps, so this would work the same way, only instead of directions, it would just be a link to the POI info of the other provider.
There is actually already a request for this at https://kagifeedback.org/d/2305-fast-way-in-maps-to-jump-to-custom-map-provider-like-google-maps/ , but it was marked as completed and apparently was on Maps version 1, but not on Maps version 2, so it isn't actually complete any more. Someone suggested opening a new feature request for it now.
