This is the API used by Digi-Dungeon for communication between servers and clients.
This API is meant to be used to create 3rd-Party clients alike the digi-dungeon-client (which uses this API extensively). You can add this to your app using:
npm install digi-dungeon-api --save
The Documentation for this API is still being written but be sure to check on Documentation.
Still barebones but Soon™️.