This is a Mozilla Firefox Add-On which helps you to open another map from the current map view.

Exemplary use case: You visit OpenStreetMap and want to know what this map area looks like in another map like Google Maps. Now you can open that map with just two mouse clicks. Search for the ShowMap toolbar icon in shape of a globe.

This Add-On is developed with the Jetpack Add-On SDK and its jpm command line tool. Unfortunately this SDK is no longer supported and does not work in current Firefox versions (57 and newer). Mozilla has switched to WebExtensions and dropped the legacy APIs. Of course some day this Add-On should be converted to be usable with the latest Firefox version, but until then Waterfox can be used for it.