Its app that just sends your heartrate from your android wear watch (Galaxy watch for a sample) to vrchat osc. Parameter names - HeartBeat(0-1 float),HeartRate2(0-1 float),HearRate3(0-255 int). Just enter your pc/quest ip and click GO.
You can install this apk with any method, for a sample with sidequest/any adb solution and enabled developer mode with wireless adb on watch.
On some devices you need to disable Bluetooth on watch, cause its some strange behaviour so watch just tries sends osc data over bt-proxy with phone, and its broken for most of the time.