There is a shelf preparing food in front of a restaurant window.
A chef is preparing food in a restaurant.
A window has to be installed in a restaurant in order to be a restaurant window.  If the shelf is in front of the window, said shelf, and the food preparation taking place on it, is located inside, or at least on the premises of, said restaurant.  Although the word "chef" technically refers to a particular type of very highly-skilled food preparer, in colloquial usage, it refers to anyone who prepares food in a restaurant.
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