CLEARPATH Turtlebot4 User Manual page 146

rqt_robot_monitor with TurtleBot 4 diagnostics
The monitor will display any errors in the first window, any warnings in the second window, and
a summary of all topics in the "All devices" section at the bottom. Each topic has a status level
of OK, WARNING, ERROR, or STALE. There is also a more detailed message included as well.
You can click on each topic to view more information.
In this example, the OAK-D node is not running, so the camera topics are not being published.