I think you’re talking about the HTML generated by Rendertron. The key point is that Rendertron is designed for search engine bots and not for user interaction. It generates static HTML for crawlers, but:
Event Listeners: React's event listeners (e.g., button click handlers) are part of the JavaScript logic, which is not included in the static HTML returned by Rendertron. This is because bots don’t need interactive functionality—just the rendered HTML for indexing.
Why Buttons Don’t Work: When you interact with the Rendertron-generated HTML, it doesn't include the React app's rehydration or JavaScript code to attach event listeners. The generated content is a snapshot, not a fully interactive React app.