Flatpak is a sandboxed application framework and standardized packaging format for Linux desktop applications. It functions as a distribution system that allows a single application bundle to run consistently across multiple Linux operating systems without requiring per-distribution builds.
The project provides a runtime dependency manager that bundles specific library versions or shared runtimes to create predictable execution environments. It includes a sandbox permission manager to control application access to system hardware and resources, ensuring security and consistent behavior between development and production.
The system manages application lifecycle through a repository distribution model, utilizing manifest-driven builds and a content-addressed version control system for updates. It integrates isolated applications with the host desktop environment via standardized portal interfaces for system notifications, global menus, and theme settings.
Diagnostic tools are available for troubleshooting isolated environments through debug shells, stacktrace retrieval, and bus traffic auditing.