Who knows the origin of the name "Yuanbaoshan Shuangluan District" in Chengde and the local folk customs?

It is said that Chengde was a small village a long time ago. One year there was a plague and many people died. There is a pharmacy in the village, which is run by a bankrupt pharmacy, but it takes the opportunity to raise the price of drugs, which makes the villagers hate it. There is a young man named Xiao Shuan who has no money to buy medicine. His two sisters died of illness one after another, and his mother fell ill on the kang. One night, just as he was in tears, he suddenly heard someone knocking at the door, and two Taoist sisters who looked like sisters floated by. The Taoist priest told him that there was an ingot-shaped stone plate on the west mountain with a hole under it. There is fairy grass in the hole. It is good to pinch it for the patient, but it is not allowed to pull it out. Xiao Shuan found the stone plate according to the instructions of the Taoist priest and pinched a few leaves. Mom really recovered after eating it. From then on, Xiao Shuan went to the cave to water Cao Xian every day and picked some leaves for the sick villagers to eat every day. After the shopkeeper knew it, he took his family up the mountain to dig out the fairy grass and plant it at home. When they came to the mouth of the cave, they saw Cao Xian moving slowly into the cave. The shopkeeper and his family were in a hurry, and the cave became deeper and darker. Suddenly the fairy grass disappeared, and the treasure thief couldn't find the hole no matter how he touched it. I haven't come out yet. There is still a jingle in Chengde that "Ganoderma lucidum in Yuanbaodong is a treasure to eliminate disasters and diseases, and whoever wants to steal it will die in the cave".