When exploring an area, these floating orbs will appear when you get nearby, and serve as both points of interest and interactive objects.
Depending on where you are, the types of items available from a node will be different. From fuel to food, or journals and souvenirs, all items can potentially be found mixed in with debris.
Sift through piles of cardboard boxes and empty bottles to search for useful salvage. Take an active part in scavenging to only take what you need to save storage space. Remove scraps of materials you do not want while making sure to collect the ones you do (or stop them from falling off).