Well, try their booking interface and compare that to Expedia.ca's. Try calling their air travel ticketing desk and compare that to Expedia.ca's. I also won't explicitly say who issues paper tickets for Expedia.ca, and who you have to return paper tickets to before you can even make any changes with Expedia (I'm not joking), even for a fully-flexible ticket.

FWIW, WWTE is an Expedia back-end for reservations. Used to be used by many airlines for their vacation reservations but you don't see it anymore with airlines like AA and AS that used to use them. Either the supplier has been changed or the back-end is now more carefully hidden.