WP-AppKit - OneSignal Only For App
When using "OneSignal for WP-AppKit" addon along with OneSignal WordPress plugin, the default behavior is to send 2 notifications: one to your website and one to your app.
This "OneSignal Only For App" micro plugin allows to avoid sending the notification to the website and send only a notification to the app.
Usage: simply download zip, then install and activate it on WordPress side as any other plugin.