Dejavu is a single-page web application that provides a modern UI for browsing, searching, and managing data in Elasticsearch and OpenSearch clusters. It is built with React 18, Redux, Redux-Saga, and Ant Design, and leverages the ReactiveSearch library for search UI components. The application runs entirely client-side, communicating directly with the Elasticsearch REST API. It supports CRUD operations, data import/export (JSON/CSV), field mapping management, term-based filtering, global search, and a search preview builder. The codebase is organized as a monorepo with two packages: a reusable browser component library (`@appbaseio/dejavu-browser`) and the main application (`dejavu-main`). The architecture follows a standard Redux pattern with sagas for side effects, and uses react-virtualized for high-performance data grids. While the code is well-structured and feature-rich, it relies on several outdated dependencies (Redux 3.x, redux-saga 0.16, react-router-dom 4.x, emotion 9.x) and uses Flow type annotations, which are now deprecated. The project appears to be in a stale maintenance state with no recent commits.