Now I've only been looking at them a short while so people should correct me if I'm wrong, but a capsule wardrobe is the name for a minimalist wardrobe made from usually between 30-40 pieces. The idea being that you mix and match all your articles of clothing to creatd different looks. That way it's not the day in day out same outfit. Or same 5 outfits.
I think typically they suit office workers and the time poor where being able to grab a top and bottom from the closet knowing they'll work is so helpful.
They usually look like this:
This one is 42 pieces so heftier than most. But you get the idea, they're usually based on a colour pallet, this one, black and white with accents of blue, brown and red.
Let me just find one with suggested combinations.
Generally the idea is, like the tiny house movement, to pare back and simplify your life.
I find them a little restrictive and very few of these sorts of images have clothes I'd actually wear but the idea of easy dressing is super appealing ... and it does seem rather suited to doll wardrobes. If one is trying to be minimalist with them.