Absolutely. That's an excellent and thorough answer, @james . Many, many thanks.
Possible text:
This add-on is intended for applications that already support OpenID Connect-based (OIDC) authentication. Apply this add-on to use Cloudron as an OpenID provider with an application that supports OIDC-based authentication.
Possible improvement for proxyauth:
The proxyauth add-on allows you to put an authentication wall in front of an application. This is useful in situations where the application has no authentication mechanisms of its own, or where there are features that you cannot easily turn off (for the general public), and you want to restrict access using Cloudron's built-in user and group management tools.
I think the idea being that, in both cases, a bit more "why" might help.
Either way, thank you. All of my questions are answered (including "oh, hey, there was an app packaging topic!").