Next we have the ICE lines, which is the mechanism chosen for NAT traversal in WebRTC. You can find a very didactic and comprehensive explanation of ICE here. ICE is complex enough to deserve its own post, but I will try to explain its SDP lines in an understandable way.
In the ICE lines above, our browser is giving its host candidates, it means, the IP of the interface or interfaces the browser is listening on the computer. The browser can receive/send SRTP and SRTCP on that IP in case there is IP visibility with some candidate of the remote peer. For example, if the other computer is on the same LAN, hosts candidates will be used. The number after the protocol (udp) – 2113937151- is the priority of the candidate. Notice that priority of host candidates is the higher than other candidates as using host candidates are more efficient in terms of use of resources. The first lines (component= 1) is for RTP and second line (component = 2) is for RTCP.