Okay. Now go to File Explorer and right click to create a new text file and try to name it “con”. That’s three letters: con. You can’t do it. Not allowed. Because CON has been reserved (in every directory on every drive) for piping to and from console since MS-DOS 2 or so. (I think 2 is when they stole pipes from Unix) Okay. Now, open just about any kind of desktop window and double click in its upper left corner. In > 9 windows out of 10 that action still closes the window even though the “close window” button was moved to the upper right corner by Windows 3. Even though a bunch of modern applications don’t even have any icon there at all any more.