Originally Posted by
Chiller3333
Those are the booking classes of the operating airlines, since that's what's decisive when miles are computed.
And for codeshares fare booking class does not always map 1 to 1
https://www.wheretocredit.com/air-canada
Note that few tickets are sold in Y fare class (usually the most expensive)
Y can be also be used generic economy covering all fares booking classes in the economy cabin.