Hey, @michalo👋 Welcome to the community! Thanks for your question. You are not missing a documented option. I agree with you, something like this would be useful. You'll either need to add comments to your HTML where smart rules are added. Like this (a super basic example):
<!-- SMART RULE: This page uses a smart rule to display different content to different visitors -->
Or you can manually check for it.
I understand this isn't the alert you are looking for. And I don't want you searching for an option that doesn't exist.