remote station's callsign
remote station's Maidenhead grid
contest exchange received
contest exchange sent
WSJT-X client name
local station's callsign
local station's Maidenhead grid
remote station's operator's name
remote stations operator's callsign (if different from station)
Propagation mode using ADIF enumerations
signal report received
signal report sent
frequency in hertz
power in watts
The QSO logged message is sent when the WSJT-X user accepts the "Log QSO" dialog by clicking the "OK" button.
See WSJT-X source.