What do you put in a motorcycle backpack+survival question?

When I get my motorcycle I wanna know what goes in those backpacks since 99% of bikers have them. I can just ume the obvious stuff, but since most bikers have them is there something I dont know? Like do they put survival things in them or what or just normal things you would carry with you? Also can you keep napalm in a tin safely? or is there another way to keep a burning product with you in a survival case/tin safely. Napalm as in gasoline+Styrofoam.