Comment 1 for bug 1803875

Typically you'd have two systems, A and B. Say you want to install ubuntu-core on B. So you create a ssh key pair on A (if you don't have one already), and associate the public key of your user account on A with your online account. You then tell the installer on B about your online account, and then you can ssh in from A without using the private key that corresponds to the public key.