Let's take a simple example of deploying Caddy on a digital ocean droplet that you are paying for. The end user in that case is you, not the people who access web pages served by Caddy since they are not receiving a copy of Caddy in the course of using your site.

To tie back to the original comment:

> It is only when you decide to embed it in an on-premises version that you sell to customers (who run it on their infrastructure) does the disclosure requirement kick in.

In that situation, when dealing with an on-premises deployment with another person or organization, the end user is the counterparty. You are required to disclose to them, but they are not required to disclose to users of their web site.

Note: this type of scenario is why AGPL emerged in the first place.