Some of them will sound familiar if you've seen rival watches. Google asked users about automatc workout detection, irregular heartbeat alerts (much like you get on an Apple Watch), breathing exercises, reproductive cycle tracking and extensive sleep tracking features that include apnea detection and smart alarms. It also wanted to know if users are interested in pairing with gym equipment and medical devices. Others are less common, though, such as SPO2 (blood oxygenation) tracking, indoor air quality data and "micro-logging" your activity.
There's no guarantee Google will implement any new features, let alone all of them. That's almost beside the point, though. This is really an indication that Google intends to compete more aggressively with Apple, Samsung and others with health-oriented smartwatches, and Fitbit's know-how could help it get there.