About the top gazebo link

In the exercise 5.2 we were asked to look at the top Gazebo tag for this file and try to guess what it does. The link tag was
<gazebo reference="world"> </gazebo>
and there were any thing defined in it. what purpose does this tag serves ?

Hello @mwk0900.na ,

This is an error in the notebook. The tag to check is the last gazebo tag of the file, not the first one. I’ve already fixed this in the notebook.