Any idea how Google digests\consumes web pages while crawling? Does it take out all the html and store just the plain text? If this is the case then can you sha

Any idea how Google digests\consumes web pages while crawling? Does it take out all the html and store just the plain text? If this is the case then can you share some more info on how they are doing it? I think there is no way they are going to scrap the websites as there are millions of them with each having their own structure.