NMEA to SignalK key assignments

[affinite]

Can someone tell me where I can look up which SignalK keys are assigned to which NMEA header?

For example the "MWV" and "VWR" NMEA sentences both include the "Apparent Wind Angle" header but in SignalK it could be assigned to /vessels/<RegExp>/environment/wind/angleTrueWater or could be assigned to /vessels/<RegExp>/environment/wind/angleTrueGround

Where can I find which SignalK key is assigned to AWA in the OP SignalK server?

I've looked through the SignalK.org site but cant find it documented.

Thanks