Is it possible for a web component to recognize, and respond, when its inner DOM contents have changed? Turns out of course it is, and the answer isn't really dependent on web components, but is a baked-in part of the web platform, the MutationObserver.
The MDN docs on MutationObserver are pretty good, as always. I won't repeat what's written there but the basics are: Define what you want to observe under a DOM element - which includes the subtree, childList, and attributes.
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