It is best not to open the found SF Express, because it may involve the sender's privacy or illegal behavior. The correct way should be to contact the courier company or the sender according to the information on the courier list and handle the courier according to their instructions. If you can't handle this problem, you can also choose to hand over the courier to the local lost and found center or courier company for handling. In short, please handle the courier you find carefully, abide by relevant laws and regulations, and protect the privacy and rights of others.