The cached HTML is rendered in Chrome (headless). When rendered, supplemental copy and links may be introduced via JavaScript, in the dom. Google will take the information it renders into consideration for indexing.
This is how Googlebot gets content from JavaScript-heavy applications. Go to Google and search for something you know renders content only with JavaScript > click the 3 dotted icon > click the Cached button > click View source > copy it and render it in Chrome to see what content appears in the dom.
Note: Update any relative paths (CSS and JS resources) to absolutes before rendering it in Chrome ^^