It can be useful to have portable apps.

If you invoke an AppImage built with a recent version of AppImageKit and have one of these special directories in place, then the configuration files will be stored alongside the AppImage. This can be useful for portable use cases, e.g., carrying an AppImage on a USB stick, along with its data.

• If there is a directory with the same name as the AppImage plus .home, then $HOME will automatically be set to it before executing the payload application
• If there is a directory with the same name as the AppImage plus .config, then $XDG_CONFIG_HOME will automatically be set to it before executing the payload application