Is this substance drywall joint compound?
I believe what I see is the paper for the drywall. There are adhesives but I see wrinkled paper if there is a filler in that point not the paper a clear photo of the tan material would be needed to make a guess. Over the years I have seen everything from sheetrock mud to modeling clay used to patch drywall with even mortar in a few cases.
Note sheetrock or drywall mud can discolor yo a brown or iron oxide color when metal corners are used and if there is moisture in the room other than the torn paper to the left of the nail I don’t see tan.