Software management on Linux is traditionally done using packages, although Linux desktop users are more interested in applications instead and do not care much about how something is packaged. Also, users often want to install software which is not available in the repositories (e.g. new applications or new versions of them), without having to upgrade the whole distribution. Listaller extends the package manager with the ability to install 3rd-party applications. It is built on top of the AppStream specs and PackageKit and focuses on system-integration. This means no additional UI must be added in order to install applications packages using Listaller. Listaller apps can be managed using existing tools like GNOME-Software or Apper. Because software from 3rd-party sources is a potential security risk, Listaller also tries to give users a hint if they can trust a certain application, and makes it possible to run these applications in a sandbox automatically. For developers, it contains some helper tools to make applications work on multiple distributions.