Hi @josephcongdon
They are the display adhesive strips and also the battery adhesive strips.
Here's the ifixit [guide|139563] guide that may help.
When removing the display most of the original adhesive will be damaged and will have to be gently cleaned off using Isopropyl Alcohol 99%+ and some sort of scraping tool and be replaced with the display adhesive supplied in the kit when reassembling the phone.
The same with the battery adhesive which ensures that the battery remains in situ