Why does "man x-terminal-emulator" return the output of "man gnome-terminal"?

Question

I know what x-terminal-emulator is and does, but I don't understand why there isn't exist a special manual page for it instead to be redirected to the manual page of gnome-terminal. I would like to see a manual page explaining what x-terminal-emulator exactly does and in that page a reference to man gnome-terminal.

Is this correct (if yes, then why, for example, the output of man dir doesn't return the output of man ls)? It is there a good motivation behind this fact?

Solution

x-terminal-emulator is a virtual package. The terminal emulator is configured by Debian's alternative system.

On Ubuntu you can easily follow this symlink construction, e.g. for gnome-terminal:

$ which x-terminal-emulator
/usr/bin/x-terminal-emulator
$ ls -lF /usr/bin/x-terminal-emulator
/usr/bin/x-terminal-emulator -> /etc/alternatives/x-terminal-emulator*
$ ls -al /etc/alternatives/x-terminal-emulator
/etc/alternatives/x-terminal-emulator -> /usr/bin/gnome-terminal.wrapper*

Now regarding the man pages, update-alternatives also links the man page of gnome-terminal to x-terminal-emulator as explained in the update-alternatives manual:

   It is often useful for a number of alternatives to be synchronized,  so
   that they are changed as a group; for example, when several versions of
   the  vi(1)  editor  are  installed,  the   man   page   referenced   by
   /usr/share/man/man1/vi.1 should correspond to the executable referenced
   by /usr/bin/vi.  update-alternatives handles this by  means  of  master
   and  slave links; when the master is changed, any associated slaves are
   changed too.  A master link and its associated slaves make  up  a  link
   group.

Source

Comments

[G-Man Says 'Reinstate Monica']

You might want to explicitly replace ll with ls -lF for the benefit of people who don’t have the “standard” aliases.  And why not use the same command on the second and third lines? Also, you should probably link to the man page you’re quoting (man7.org/linux/man-pages/man1/update-alternatives.1.html).

[Sylvain Pineau]

@G-ManSays'ReinstateMonica' good idea, thx.