@AndyR, the pages for the device have always been retrieved from the cloud. The option exists to use the SD card if you wish which has been described in the solutions on the support site (https://opensprinkler.freshdesk.com/support/solutions/articles/5000011026-using-the-sd-card-for-ui).
If you are curious, you will notice it references home.js (inside my app’s /js folder). This is the loader that ends up loading my app into the browser and connecting to the device.