UI is the Elm application that'll be executed on the main thread (ie. the UI thread) and Brain is the Elm application that'll live inside a web worker. UI will be the main application and Brain does the heavy lifting. The code shared between these two applications lives in Library. The library also contains the more "generic" code that's not necessarily tied to one or the other. Additionally you have Themes which is a layer on top of the UI code.

Emoji Comments#

⛩    Gates (Flags & Ports)
🌳    Types & Initial State
📣    Updates
📰    Subscriptions
🗺    Views

🧠    Brain
🛠️    Functions
🖼    Styles
㊙️    Secret