Lightning Network conf listen & externalip values I downloaded LN repo. I have this settings in my lnd.conf file:

listen=192.168.100.134
externalip=186.4.235.84


I am following some tutorials online that do not include this settings (like this one) . Can someone explain the role of this variables please? I am not a network expert and I like to understand the code I write.
Listen: This specifies the interfaces to listen to for incoming connections to your node. This will allow other nodes to establish inbound connections to your lnd node. If you want to listen to all ipv4 connections on port 9735, you can use listen = 0.0.0.0:9735

External IP: Adding an external IP advertises your node to the network. If you'd like to signal to other nodes on the network that you'll accept incoming channels (as peers need to connect inbound to initiate a channel funding workflow), then the externalip flag should be set to your publicly reachable IP address.