Earlier quoted context omitted.
Additional advice: "don't use this toolkit if you ever want to sell your product to government".
Which is interesting because I use a dialysis machine and these are essentially sold to the government instead of the patient yet they all use a custom GUI interface like this one. Far as I can tell there is no accessibility features.
In my ideal world, all user interfaces would run on the user's main portable computer (currently a smartphone), controlling devices remotely over Bluetooth, NFC, or the like. Embedded UIs would then be a thing of the past, and accessibility would simply be a matter of following the recommended practices for mainstream general-purpose platforms.