Broadcast mode is aimed at broadcasting and recording services where you want to pass only the video on to your viewers. They won't see the icons, controls and messages that are typically meant only for the person in the room.
To set a device to broadcast mode:
Log into the device's local web interface.
Go to Settings > Configurations.
Scroll down and select UserInterface.
Scroll to OSD > Mode and select Unobstructed.
Set to Auto (default), the device will run in normal mode and indicators, notifications and controls will be included in the video stream as usual.