nixpkgs/nixos/modules/services/desktops/flatpak.xml

<chapter xmlns="http://docbook.org/ns/docbook"
         xmlns:xlink="http://www.w3.org/1999/xlink"
         xmlns:xi="http://www.w3.org/2001/XInclude"
         version="5.0"
         xml:id="module-services-flatpak">
 <title>Flatpak</title>
 <para>
  <emphasis>Source:</emphasis>
  <filename>modules/services/desktop/flatpak.nix</filename>
 </para>
 <para>
  <emphasis>Upstream documentation:</emphasis>
  <link xlink:href="https://github.com/flatpak/flatpak/wiki"/>
 </para>
 <para>
  Flatpak is a system for building, distributing, and running sandboxed desktop
  applications on Linux.
 </para>
 <para>
  To enable Flatpak, add the following to your
  <filename>configuration.nix</filename>:
<programlisting>
  <xref linkend="opt-services.flatpak.enable"/> = true;
  </programlisting>
 </para>
 <para>
  For the sandboxed apps to work correctly, desktop integration portals need to
  be installed. If you run GNOME, this will be handled automatically for you;
  in other cases, you will need to add something like the following to your
  <filename>configuration.nix</filename>:
<programlisting>
  <xref linkend="opt-services.flatpak.extraPortals"/> = [ pkgs.xdg-desktop-portal-gtk ];
  </programlisting>
 </para>
 <para>
  Then, you will need to add a repository, for example,
  <link xlink:href="https://github.com/flatpak/flatpak/wiki">Flathub</link>,
  either using the following commands:
<programlisting>
  flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
  flatpak update
  </programlisting>
  or by opening the
  <link xlink:href="https://flathub.org/repo/flathub.flatpakrepo">repository
  file</link> in GNOME Software.
 </para>
 <para>
  Finally, you can search and install programs:
<programlisting>
  flatpak search bustle
  flatpak install flathub org.freedesktop.Bustle
  flatpak run org.freedesktop.Bustle
  </programlisting>
  Again, GNOME Software offers graphical interface for these tasks.
 </para>
</chapter>