What are the origins and legends of Tomb-Sweeping Day?

Tomb-Sweeping Day was developed from the Cold Food Festival. There is such a legend:

During the Spring and Autumn Period, Jin Wengong Zhong Er was exiled, tired and hungry on the way. He cut a piece of meat from his thigh with a minister's leg and cooked soup for Zhong Er. Zhong Er was very grateful when he learned that. After Jin Wengong ascended the throne, he raised his minister, but forgot to recommend him. Jiezitui does not admire fame and fortune, and lives in seclusion in Mianshan.

Zhong Er regretted burning Mianshan to find Jiexiu, only to find that Jiexiu died in a yellow Liuxia, carrying his mother on his back and leaving his last words: "May Master always be clear." To commemorate meson tui, Jin Wengong designated this day as Cold Food Festival.

In the second year, Jin Wengong personally led the civil and military officials up the mountain to worship Jiexiu, only to find that the old willow tree that burned Jiexiu's mother and son came back from the dead. He immediately gave the old willow the title of "Qingming Willow" in the Year of the Monkey, and took the day after the cold food as Tomb-Sweeping Day.

Tomb-Sweeping Day originated in the Spring and Autumn Period. During Jin Wengong's exile, Xietui minister cut meat and cooked soup for him, but Jin Wengong forgot Xietui after he ascended the throne. Jin Wengong regretted it and set fire to Mianshan to find it. Afterwards, I learned that meson push was dead. To commemorate meson tui, Jin Wengong designated this day as Cold Food Festival. In the second year, Jin Wengong personally went up the mountain to worship Jiexiu, and found that the willow burned to death by Jiexiu actually came back from the dead. Therefore, Jin Wengong designated the day after the Cold Food Festival as Tomb-Sweeping Day.