On the left, it says "a certain year, a certain month and a certain day": this is just like an envelope for sending a letter. I really can't think of such a writing method, so it's no problem to write it in an envelope.
July and a half (Mid-Autumn Festival) The custom of July and a half in the lunar calendar, commonly known as the Mid-Autumn Festival, is also called Ghost Festival, which is a relatively heavy folk festival. Every year until the beginning of July, every household will take the old people home for sacrifice and prepare to burn buns for them. According to legend, as soon as the gate of hell was opened on the first day of July, Yan Ye released all the ghosts and let them enjoy the annual "holiday". The souls of the dead ancestors returned to the earth to check the good and evil of their descendants, and the dead held some worship activities to entertain them, especially the Mid-Autumn Festival.