That dumpling is literally the old school Chinese MRE. Imagine the Chinese fighter that looks like Genghis Khan battalion riding on a horse, with a stash of grenades looked a like (wrapped in lotus leaf, from far it does looks like army camouflage

Sauce

Ok I made that up. I know I'm full of crap. But there's a lot more superstitious claims on the festival if you wanna dig into this Chinese MRE grenades. One of the most significant would be a Chinese minister throw himself into the river after he was banished of opposing the alliance and accused for treason. People start throwing MRE grenades into the river so the fishes doesn't eat the guy's body. More readings in Wikipedia, but don't bother. I can write better story rotfflmfao