You searched for CHANNEL ANNOUNCEMENTS
1. channel announcements
Syntax: @ announcements on|off
This will toggle announcements on channels on or off. A message will be
displayed in the channel when a player joins or leaves the channel, if the
channel expires or is deleted, when someone is banned or unbanned, when
someone is given access to the channel, when someone unlocks the channel,
and when there is a new owner or moderator.
This toggle does not disable messages from the announcements channel itself.