API KEY for Google Maps的作者是GeoDirectory，目前有100,000+个有效安装。已经Tested with 5.1.5版本的wordpress。
Retroactively add Google Maps API KEY to any theme or plugin.
Simply activate, go to Settings>Google API KEY and enter your key.
The plugin will then attempt to add this key to all the places it is needed on the front of your website.
NOTE: this will only work if the Google API has been added as per WordPress standards)
The plugin was created by the GeoDirectory team: http://wpgeodirectory.com