How to find hidden / not rendered html in a web page?

For example : In the following web page : https://geizhals.de/?cat=umtsover. doing inspect elements i find that some portion of code is not rendered by the browser, but present in html. Is there any way to detect this ?

I know there can be few heuristics that could be derived for some specific web pages. But is there any generic way to do this ? Assuming I have CSS ( where i could use visibility attributes ) and also if i dont have css info ?

Any help would be appreciated.