Depends on the kit.

For the most minimal, there isn't room for anything to cook with. *shrugs* Chlorine tabs for water.

My ditch kit in it's current configuration has the outer pieces of a French mess kit, and a small Esbit stove. I have a small vial each of salt and chili powder, a couple of ramen seasoning packs and a small spoon. Brew kit has lemon crystals.

My BOB/camping bag has this . I carry two pint bottles of denatured to fuel the trangia, along with a small platform so it can use Esbit or triox tabs and candles, and I carry spare Esbit tabs in my pack. It will also burn small wood or other solid fuels. To cook in, I've got a 1.7L storage canister that has been drafted to serve as a cook pot (works very well, and much more robust than the grease pot it replaces) and two Nalgene cups. Lexan spoon and fork, and a big vial of salt, small vials each of black pepper, chili, garlic and curry powders, and eight assorted ramen seasoning packs. Brew kit has both lemon and lime crystals.