Among the "hardware" paid by the company for its employees, what is the "medical financial fund"?

I don't understand the medical financial fund, which means that the state collects relevant premiums and manages them in a unified manner. The medical reimbursement is based on the principle of universal public benefit and mutual financial assistance.

For example, if A, B, and C all purchased medical insurance, not all of them will get sick after purchasing it. Maybe B will get sick this year, so the money paid by the three will be reimbursed for B's medical subsidy.

Therefore, this is called the so-called "medical financial fund".