[TUHS] Origin of the MOTD file?

[Jeremy C. Reed]

(A similar question was asked a month ago here. From my response then 
...)

v1 has the concept "message of the day"
http://minnie.tuhs.org/cgi-bin/utree.pl?file=V1/man/man7/login.7
but I don't find the code for it.

v2 login reads "/etc/motd"
http://minnie.tuhs.org/cgi-bin/utree.pl?file=V2/cmd/login.s

By the way, where is the code for the shell referenced in init.s for 
the earlier Unix? http://minnie.tuhs.org/cgi-bin/utree.pl?file=PDP7-Unix