This directory contains part of the browser side implementation of the native file system API.
See https://wicg.github.io/file-system-access/ for the spec for this API.
//storage/browser/file_system/ contains the backend this API is built on top of, blink/renderer/modules/file_system_access contains the renderer side implementation and blink/public/mojom/file_system_access contains the mojom interfaces for these APIs.