- Submit a file to Special:fileimport
- click "Edit File Info"
- Empty the text in the editor
- Save
-> Result: The old info is still there.
- Submit a file to Special:fileimport
- click "Edit File Info"
- Change the text to something
- click Save, you see the changed content rendered on the importpage
- click "Edit File Info" again
- Empty the text in the editor
- Save
-> Result: The original info is there again.