This config is set by the Pirate Audio install script- https://github.com/pimoroni/pirate-audio/blob/master/mopidy/install.sh
Since this library is device agnostic, these defaults don't have to be here, and shouldn't be here. Users should have to explicitly configure and enable the plugin.
See #9 for an example of the default pin config being unexpectedly loaded and causing the plugin to bail.
Philip Howard