This addon allows candidates to apply to jobs via email using their Facebook profile. This plugin makes use of a Facebook app which you will create for your site. When a candidate clicks this button, the plugin will open a window allowing the candidate to log in to Facebook. To use this plugin you’ll need a Facebook developer account and you’ll need to create an app.
This is the EXACT same plugin as distributed by the developer on WP Job Manager. The developers’ links are provided above.