Usage: CLIENT <class> MOTD INSERT <line> <text>

This command will insert a line of text into the MOTD The text will be inserted above whichever line number is sent in the command.

/as client z-default motd insert 1 Now this is the first line of the motd.

This is an easy way to edit the motd. If you left something out, you can insert it. If you made a mistake in a line, you can delete it and insert a replacement where it was.