Ah, I didn't see the uWatch app before, I guess it was never in OpenStore? Based on the limited number of responses it lookes like PineTime might be the second most popular one after Pebble. I also had no idea it shipped with a default OS, no info on the store page (but that makes things easier).
@mymike Which model is that? I'll probably get a Garmin once I get back to running properly
Though if it syncs with WiFi a lot of the functionality might not be possible without an account and the official app. Sniffing BT is not hard, but the log file contains all Bluetooth traffic the phone participated in, and even if you filter it for the watch only, that can potentially still contain personal/confidential information (notification content, health data, etc). Not something you want to share imo.