“The “before” HTML I looked at was the raw HTML sent over the wire. The “after” HTML I looked at was a stringification of the DOM after a couple seconds of first requesting the URL. The string is a representation of what the browser decides to output if you click “Edit as HTML” on the root DOM node and then copy it. In other words, it’s the browser’s version of saying “you input HTML, I parsed it, executed relevant JavaScript, and now have this HTML representation.””
