Plane is an open-source, self-hosted project management platform that provides issue tracking, sprint planning (cycles), modules, pages (wiki), views, analytics, and real-time collaborative editing. The repository is a monorepo containing a Django REST API backend with Celery workers, multiple React frontends (main web app, public space app, admin panel), and a Hocuspocus-based live collaboration server. The architecture follows a service-oriented pattern with shared packages for UI components, editor extensions, types, utilities, and state management via MobX. The codebase demonstrates strong engineering practices with a rich filter system, extensible permission model, and a clean exporter pattern, though it shows signs of ongoing migration from Next.js to React Router and some code duplication across apps.