This app runs a service that will launch https://f-droid.org/packages/ch.blinkenlights.android.vanilla
whenever Android broadcasts a HEADSET_PLUG event.

Please note that you need to start the application at least once in order to
launch the persistent background service. Also note that the application is
useless unless https://f-droid.org/packages/ch.blinkenlights.android.vanilla is installed on your device.