Get on their discord. Bangle has the JS thing, pebble watch faces used a c-variant, I don't remember if their applets used something different. AFAIK, if you'r

Get on their discord. Bangle has the JS thing, pebble watch faces used a c-variant, I don't remember if their applets used something different. AFAIK, if you're doing firmware replacements you're likely going to be maintaining an "out of tree fork" unless it's already well-modularized in the way you're imagining.