It is the category of room that you have booked.
Each hotel is signified by a letter to let the reservation center know what resort you are booked at and that is followed by the letter of the categorey that you have booked. The Contemporary's Descriptor code is "C" so that tells them your reservation is at the Contemporary, I am not familiar with the categorey descriptors at the Contemporary to know what the F means, but I would assume that it means MK or Bay lake View... I can give you an example using the Wilderness Lodge (I worked there, so it is the only example I have for an explination) so here goes Wilderness Lodge is hotel "J" so the categories there are JA-Standard view, JB- Woods view, JC- Courtyard view, JD-Concierge, JH- Honeymoon Suite, JS- Deluxe Room, JV- Vice Pres, JP- Pres and they just added JE (bunk beds woods view) and JF (Bunk Beds Courtyard view)... Sorry I don't know what the view descriptors are at Contemporary, but I hope that helps to answer the question a little bit!