zulip/templates/zerver/help/the-announce-stream.md

The #announce stream

The #announce stream is just like other streams in most ways, but it's conventionally used for organization-wide announcements.

By default, everybody is subscribed to this stream. For this reason, you'll want to keep the traffic on it low, so that people don't mute it and miss an important announcement.

Additionally, Zulip's notification bot uses this stream for its messages.