more first, last control ideas, header limits

Also good would be
--headers --limit 15 --from-bottom --from-top etc. options,
to only show e.g., 15 headers from the top or the bottom of the mailbox.
much more efficient than mail -H|head -n 15, |tail -n 15.

(Odd, on (info "(mailutils) Mail Variables")
there is no variable that controls how many header lines are shown,
when interactive, or when using --headers.
There is just

'screen'

     Type: Numeric.
     Default: Detected at startup by querying the terminal device.  If
     this fails, the value of environment variable 'LINES' is used.

     This variable contains the number of lines on terminal screen.

but this does not mention its relation to the number of headers shown,
if any.)

Also
$ mail --start-on-last-page, --start-on-first-page
to override where it wants to start on.

And --put-arrow-on-first-message-on-screen
--put-arrow-on-last-message-on-screen etc.