According to the Ladenschlussgesetz, gas stations in Germany are allowed to be opened during the night and Sundays, but are only allowed to sell gas, car things (like oil) that are needed for people to travel onwards and
(my attempt at a translation: travel necessities)
Now, I have been at a gas station on Sundays and at night many times and it did not appear like they change what they sell for those times. Meaning they still sell, for example, alcohol, frozen pizzas, flowers, shaving gel, etc.
Is "Reisebedarf" defined anywhere?