grammar - A weird case : "The kitchen’s window" vs "The kitchen window"

I just came across this article (noun modifiers), and I'm surprised that these two nouns mean different things:

The kitchen’s window

The kitchen window

The Ngram shows zero usage of the first one even though it's very common .

Here are some articles using the first one ( The kitchen’s window ):

The New York Times Making a New House Look Old

The kitchen’s window and door combination has an arch similar to that
of the brick-in arch elsewhere in the facade.

One biotech gasps for breath

[...] and an assortment of sweets soon cover a long table by the
kitchen's window .

How come?
Thanks.

Update :

Thanks to @Lawrence, I've noticed that there is an Ngram apostrophe issue, and that's why it shows zero usage of kitchen's window . To workaround this issue, I used a wildcard and here is the result of the kitchen * window
( Please, click on search lots of books to see the result ):

Answer

First off, in the source sentence:

The kitchen’s window and door combination has an arch similar to that
of the brick-in arch elsewhere in the facade.

The possessive "kitchen's" does not modify "window", but rather "window and door combination". If one did use "kitchen" in this context the reader might well be led down the garden path to concluding that the reference was to a door/window combo similar to that that might be used in a kitchen (even though, in this case you could be talking about a bedroom).

And in the second source sentence:

[...] and an assortment of sweets soon cover a long table by the
kitchen's window .

What's being described is the layout of the kitchen. Thus a specific window is being referred to, and window is not so much a feature of the kitchen but rather a "landmark".

As with most things English, the rules are mushy, but the non-possessive use of "kitchen" to modify "window" implies a window of the type used in a kitchen, while the possessive implies a window which is "owned" by the kitchen.

There is plenty of room for both forms to be used, depending on context.