google.apikey

Smartsite 7.8 - ...

You can use this appSetting to specify a single Google API key for all the Google related services used within the Smartsite 7 Manager.
(Which currently includes Google Maps, YouTube and Google Pagespeed.)

To obtain an API key and/or enable additional services for a specific API key, browse to https://console.developers.google.com/

When this appSetting is not present, each service needs to have it's own API key appSetting, respectively: googlemaps.apikey, youtube.apikey and google.pagespeed.apikey.