Flatpak

Flatpak is a universal packaging system and runtime for installing packages separate from the system packages. Mainly meant for desktop applications, Flatpak allows application developers to distribute packages without needing to worry about distro compatibility because Flatpak installs its own runtime dependencies. It claims to improve security through sandboxing providing the user the ability to give or revoke permissions for a given application. Flatpak is installed by default on many distributions and it's main distribution platform is Flathub.

Installation

Flatpak comes preinstalled on many distributions such as Linux Mint and Fedora but can be installed through most distro's package repositories if not present.

KDE Discover

KDE Discover includes the ability to install Flatpak and enable Flathub through its graphical user interface. Go to the setting tab and install the Flatpak backend then restart Discover then go back to the settings and enable Flathub.

CLI Install on Ubuntu

To install Flatpak from the CLI run:

sudo apt install flatpak

To enable Flathub from the CLI run:

flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo

If you make use of GNOME Software you can install the integration plugin:

sudo apt install gnome-software-plugin-flatpak

For the KDE Discover plugin run:

sudo apt install plasma-discover-backend-flatpak

For other distros read the guides on Flathub.org.

Compatibility

Flatpak allows improved package compatibility through its use of its own runtime dependencies. Packages can run through Flatpak where it might not be possible to run on natively such as:

• Applications that require a newer version of glibc than whats available on an stable release distro such as Rocky Linux 8.
• Applications that depend on glibc such as Steam running on a distro using musl like Alpine Linux.
• Multilib packages such as Steam or Wine on distros without multilib support such as CentOS Stream 10.

Sandboxing

Package permissions can be managed by the user through a graphical user interface with Flatseal which can be installed as a Flatpak.

Flathub Package Verification

Flathub has a package verification system that allows packages maintained by the official developers to have a verification tick. This has lead to some confusion where verification is mistaken for package safety. Linux Mint hides unverified Flatpaks from Software Manager by default Starting in version 22.