Add a headsup (in the Readme) along the line:

When the Fether application is started through the bundled AppImage package, there are
configuration options for AppImage itself before it starts the Fether application. Specifically,
when creating a directory with the same name as the binary, ending in .home, the directory
will be used as the value for $HOME . This presents a potential risk when a user executes the
Fether application, since external actors could control the $HOME directory used by Fether,
which is responsible for storing keys and local cache data. The AppImage system will only
perform this operation when the .home directory is accessible to the user
executing the AppImage package.