Every restaurant serves dishes that are assembled from prepared components.
In good independent restaurants, everything will be made on the premises, but if you order slow-cooked beef or confit duck, this must have been cooked in advance. Classical French restaurant cookery is based on using pre-made "mother sauces" (béchamel, velouté, espagnole, hollandaise, and tomato) in different combinations to make a whole range of dishes. The kitchen will be set up to use these components to assemble dishes reasonably quickly when orders come in.
At the other extreme, in cheap places such as chain pubs with suspiciously long menus, many dishes could well be little different from supermarket ready-meals, heated up and plated to serve with e.g. a handful of leaves or some chips added.
There will be a whole spectrum of things in between - for example, a "quality" restaurant chain might well have a central facility to make the sorts of components that any restaurant has to precook. This will help them to ensure consistency between branches. The overall process might be little different from that in a top independent place, it's just that not all the stages of preparing the food take place on the same site.
If you've ever ordered food from somewhere like "Cote at Home" then I would guess that many restaurant chains would deliver food to their branches in pretty much the same way as these work - pre-made sauces, slow-cooked meat in sous-vide packs, etc. Indeed, I've always sort of assumed Cote launched this service as quickly as they did when their restaurants had to close due to COVID precisely because they were left with a central facility that had the capacity to crank out dishes but nowhere to sell them!