This repository is a highly configurable, feature-rich React date picker component library published as `react-datepicker`. It provides a single entry point (`DatePicker`) that supports single date, date range, multiple dates, week, month, quarter, and year picker modes, along with time selection, timezone handling, localization via `date-fns`, and extensive keyboard navigation and ARIA accessibility. Internally, the library uses a class-component architecture with a clear separation of concerns: a `Calendar` component manages month/year navigation, `Month` renders days or month/quarter grids, `Day` handles individual cell rendering with selection and focus management, and `Time`/`InputTime` handle time input. Positioning of the calendar popover is delegated to `@floating-ui/react` via a `withFloating` HOC, and rendering can be redirected to a portal (including shadow DOM) for overlay scenarios. The component exposes over 60 props for customization, including custom input elements, headers, and day rendering. The library is mature and widely adopted, with a comprehensive test suite (Jest + React Testing Library) covering interactions, keyboard navigation, edge cases, and accessibility (axe tests). The build pipeline uses Rollup to produce UMD, CJS, and ES module bundles, and CSS is provided in both standard and CSS Modules variants.