.flatpak File — Flatpak Application

Flatpak is a universal Linux application distribution framework that provides sandboxed applications with bundled dependencies. Flatpak packages contain the application and its runtime dependencies in a format based on OSTree (a versioning filesystem). Applications run in sandboxed environments using Linux kernel features (namespaces, cgroups, seccomp) and Bubblewrap, with access to system resources controlled through a portal system that provides controlled access to files, printing, notifications, and other capabilities. Flatpak uses a layered approach — runtimes provide common libraries shared across applications, while applications add only their specific dependencies, reducing overall disk usage compared to fully bundled packages. Flathub is the primary repository for Flatpak applications, hosting thousands of applications maintained by the community and application developers. Flatpak is supported by major Linux distributions including Fedora (default), Linux Mint, elementary OS, and many others. The format supports automatic delta updates (downloading only changed files), multiple parallel installations (different versions coexisting), and per-application permissions that users can customize. The Flatpak approach emphasizes decentralized distribution and user-controlled security.