Zapta designed this open source ARM M0 microcontroller board, that is available at Github:
ARM PRO MINI is a small barebone open source ARM M0 microcontroller board that is great for quick prototyping and as a starting point for your own ARM based custom designs. It was designed and named after the venerable Arduino Pro Mini and it is an excellent stepping stone for makers and hobbyists ‘graduating’ from Arduino to the ARM architecture.
Via the contact form.
ARM Pro Mini is not a good name for an open source board, because you’d have to rely on ARM legal dept allowing this. Personally I wouldn’t even try this kind of thing, because I think it’s not polite to do so. Naming your board with ‘ARM’ in it is vastly different from listing ARM M0 in the specs.
Legacy Interactive Mini Board? Not an ARM, but a LIMB…