I read a post that mentioned something about the bag awning being placed inside the camper before leaving a site.
In the beginning, there was just "The Awning." It was simple, but a pain to erect, and to pack, and to store. There was no bag attached to it.
It had to be attached to the trailer's awning rail when you set up camp, and it had to be removed from the trailer when you packed up and got on the road. Much like a tent or canopy, it has separate poles and separate guy ropes that need to be staked to the ground. When you broke camp, you probably placed the unattached awning, along with the poles and ropes into a separate bag and stored it inside the trailer.
I believe this is the type of awning you read about.
In an effort to make having an awning a better experience for the person who has to actually set up and break camp, different kinds of awnings were developed which could be permanently attached to the outside of the trailer. They are:
The differences are in the way they are attached to the trailer, and in the way they are unfurled and stored, without quite so much assembly or dis-assembly required.