It essentially means that you have to have a real reason not to have windows, not just "it was slightly cheaper". So new buildings would get them, intentionally windowless spaces (darkrooms, freezers) are allowed for a purpose, and adapted historical buildings are allowed.

It definitely does not apply to restaurant kitchens. For older buildings not at all -- plenty of totally windowless and even basement kitchens -- and even for newer buildings I think "serving station open to the restaurant floor" counts as "natural light" (and actually isn't all that bad).

Where I just had lunch they get natural light whenever a waiter opens the door to bring some food out.

Source: I live in the EU and have been inside a lot of restaurant kitchens in both Germany and Hungary.

It’s the EU, so you can count on it being reasonable.

The example I know of where it isn’t enforced is of people working inside a refrigerator. I can imagine security conscious jobs and radiology departments also may be exceptions.

It also doesn’t mean all rooms need windows or even natural light. Toilet rooms often don’t, for example, and storage rooms often only have windows high in the walls or in the ceiling (typically way more than in “a room with a view” in Cupertino :-) )

> I wonder how that is interpreted?

* If the nature of what goes on inside a room conflicts with the presence of windows -- e.g. labs (say, a laser lab)

* if the room isn't meant to be used by humans (e.g. storage closets, server rooms) -- If humans sometimes enter such rooms that's OK, but it can't be their "assigned workplace".