Differences between WWDC Video and Sample Application

Why are there differences between the Sample application in the download and the code presented in the video? Specifically there are different Imports. I noticed that when I made references to some of the AR functions in. change I made it would not compile clean until I added an import of the ARKit and the Reality Kit even though both are in the RoomPlan import. Does the scope of definitinons get limited to that of the Imported symbols?

Differences between WWDC Video and Sample Application
 
 
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