Flatpak is a containerized package format for Unix-like/POSIX-compliant operating systems. Flatpaks require the Flatpak utility to run, are automatically sandboxed, and can only access permissions you specifically grant them via portals. They're very helpful for installing applications that your specific distro could not support otherwise, packages you do not fully trust with your data, or proprietary software. As a trade-off, they are much heavier than normal packages.What is Flatpak?