addr messages contain the addresses of other nodes. It's how IP addresses for other nodes are spread around the network.
That's true most of the times but I'm talking about when nodes send you their own
addr message.
Let me put it this way, I connect to 185.132.178.23:18333 (satoshi 0.20.0) and send it a
version message saying I know you are 185.132.178.23:18333 (in the receiving node address part), I've also connected to it so I already knew that. Then it sends me its own
version message that can contain 185.132.178.23:18333 again (but it doesn't but that's irrelevant for now). After the handshake is finished it sends me an
addr message saying 185.132.178.23:18333 is an address of a node!
I'm trying to figure out what the reason behind all this repetition is, specifically the last
addr part.