I'ts not part of consensus, just a way to find initial peers (other nodes). Originally instead of this there was single hardcoded IRC channel on single IRC server (#bitcoin on Freenode). Any user can use addnode= to manually add different peer from the start and then that peer will be used to discover other peers too (and if you help setting up node to your friend, it's good idea to addnode= your node in config for him).
But it's good that you are going through code, don't trust - verify!
#bitcoinonFreenode). Any user can useaddnode=to manually add different peer from the start and then that peer will be used to discover other peers too (and if you help setting up node to your friend, it's good idea toaddnode=your node in config for him).