Using drag and drop actually moves files if target is GNOME Files
Completed chapter 13 "Drag and Drop" - Dragging Objects to an Outside Application. After dropping files into GNOME Files (Nautilus) application files are actually moved. First I was very surprised, as Flatpak was set up to use home directory in read-only mode, and I was expecting that all operations should be sandboxed. Good thing I didn't move anything important
Maybe readers should be informed about possibility of making unexpected changes to their filesystem, just by playing around with drag and drop?