= Sell Seat
MX968 = Flight Number
Q = Booking Class
12AUG = Flight Date
= passive booking, confirmed seat
1 = 1 seat
= not sure, but usually you enter the Filekey/PNR of the airline here - so I guess that the flights were booked directly through MX
In other words: you were preparing bookings that were not made directly at your office for ticketing at your office, something that is done through passive segments (a segment that represents an active segment that is booked in another system and/or in another office) - a passive segment does not reduce the availability inventory of the flight by the number of seats booked, because it's passive... the active segment (the real segment) already took the seat out of the inventory.
Hope I explained that in a somewhat understandable way...