It's in the MH manual under FOLDER HANDLING/Relative Folder
Addressing. It is not in the man pages. But back when I was new at
this I actually read the manual.
Ah, I see it. I haven't read the user's manual since then, either,
and I didn't find it when I grepped through the documentation.
I looked through the "papers/" directory and at all the installed
manual pages.
I see two MH documentation problems. First, the @ notation should be
in the folder(1) manual page.
Second, there are several non-manuals hidden in the manual page
directory. The documentation in ADMIN.* and MH.* would stand out more
in a separate directory. Hmm...I see that MH.me wants to include all
the other documents, so having it in the same directory is useful.
Well, it would help if there were a README file in the directory
pointing out that two of the files here were not like the others.
< Stephen