network – What is the purpose of addr_recv? What does it mean that addr_recv affects the heuristic for determining which of the receiving node IPs is public?

Here I found the purpose of addr_recv and addr_from.

Bitcoin Core actually ignores it. addr_from From the received version message.
addr_recv Used to influence a heuristic for determining which of the receiving node’s IP addresses are publicly accessible.

But I don’t know what this was written for. addr_recv.

Can someone explain their purpose? addr_recv More details? How does addr_recv affect the heuristic for determining which of the receiving node IPs is public?