undocumented stty speeds

[Dan Jacobson]

I am on a page of Info called Special, that must be related to stty.

`N'
     Set the input and output speeds to N.  N can be one of: 0 50 75
     110 134 134.5 150 200 300 600 1200 1800 2400 4800 9600 19200 38400
     `exta' `extb'.  `exta' is the same as 19200; `extb' is the same as
     38400.  0 hangs up the line if `-clocal' is set.

# stty 115201
stty: invalid argument `115201'
Try `stty --help' for more information.
# stty 115200
#
Whahaha, I discovered a undocumented prime number.

And --help just says
   speed         print the terminal speed
which doesn't even instead say "print/set".