On my Windows 10 Pro guest I have "file" named Windows 10, 0 bytes, which isn't assigned to any application (no extension) and which also cannot be moved to the waste basket.
It jumps out of the trash. But I believe the reason was that it was a relict of the Windows VM that I deleted.
I was with one foot in an xterm in the directory that I had previously deleted.
I have deleted the VM again and reinstalled Windows 10. Now the file is gone.