You can export empty package

2) How can we reproduce it using the example you attached
1 Create new project
2 Select Assets folder and select main menu->Assets->Export Package
3 In appeared window deselect Assets folder (turn off check box) and press Export-button -
so you created empty package (maybe it is ok)

When exporting from a project with no assets the export window display a message related to no asset to "import" can be confusing.

4 Next try to import this package back to Unity - you will get window with text "All assets from this package are already in your project"
Expected result: think this text should be something like "Empty package" or smth like that