Looking at https://github.com/ethereum/wiki/wiki/enode-url-format and https://github.com/ethereum/go-ethereum/wiki/Connecting-to-the-network I can see that the enode URL includes some information about the node.
Here's an example enode URL:
enode://3414c01c19aa75a34f2dbd2f8d0898dc79d6b219ad77f8155abf1a287ce2ba60f14998a3a98c0cf14915eabfdacf914a92b27a01769de18fa2d049dbf4c17694@[::]:30303 - the part between
@ is the username.
Everything else seems ok, but what is the username / node ID part? The answer at https://ethereum.stackexchange.com/a/1196/31933 says it's some public key, but a public key for what?
As accounts and nodes are not directly related (accounts just utilize nodes) it can't be anything account-specific (such as account's public key). So if it is a public key, who has the private key and what can it be used for?