Architecture
For contributors, the interesting detail is the Koa server running in a worker thread inside the player. The Electron UI (and any other client) talks to the player over a REST API; the playback engine drives the controllers.
The REST surface is documented in full under
REST Interface (HTTP API). Runtime and build-time configuration
via environment variables is listed in
Environment Variables. This diagram is compiled from
doc/assets/diagrams/ezp-arch-dev.d2 and is shared with the developer slide deck.