Why are wontons called "wontons" in Tianjin?

In my memory, this one appeared together with the casserole. At that time, the streets were full of casserole wontons. At that time, I only knew that this was the name in the south, and the way it was packaged was also different.

The biggest difference between casserole wontons and wontons eaten before is that they are cooked in one bowl, not in a big pot.

Then, wontons gradually replaced wontons and became one of the four kings of Tianjin breakfast (laodoufu, rice crispy rice, glutinous rice paste, and wontons).

Also born at the same time was water chestnut soup, a halal version of chicken soup with mutton filling.