The juju info interface is a special and implicit relationship that works with subordinate charms. When building from layers, if your subordinate uses this interface, you will implicitly receive private-address.
There is no provides or peering mechanism on this interface.
Both states signify the subordinate is successfully connected to the parent "container".
Note: these states key off of what the charm author names the relationship which should not be the name of the interface:
An example of a properly implemented relationship would resemble the following:
requires: host-system: interface: juju-info
The respective states in your charm would then be: