The graph is the only thing the apps share. It is one API with six endpoints, and it holds every card. No app has a database of its own.
Each app is a different stack on its own address. It reads and writes the cards over HTTP and listens to one stream of events from the server.
Lines count only the source a person wrote, counted by a script after each build. Download is what the browser receives, compressed, with the fonts and runtimes included.
The line of changes shows real events. A frame lights when its app sends a change, and every frame flashes at the moment its own app has drawn it. Every time shown is measured, not estimated.
Type: Familjen Grotesk (SIL Open Font Licence). Stack marks from Simple Icons (CC0).