A Developer's Certificate of Origin is a document that developers sign to show that their code is original and that they own it. It's like a contract that says the code was made by them and that they agree to share it with others who also agree to this document. By signing the Certificate of Origin, developers are saying that they created the code and are giving other people permission to use it. They also promise that their code doesn't violate anyone else's copyright, patent, or another type of intellectual property.