What method of scraping is used in the read PDF text activity?

By scraping, I don’t mean screen scraping of course, because if i’m not wrong, screen scraping is when there’s a screen to scrape from. As in, the document’s UI elements are visible for us to show the robot what to scrape, and then, during the execution, the application should be open. (You can correct me if I’m wrong). By scraping i mean extraction of data ( as mentioned in the following link: https://www.uipath.com/kb-articles/scraping-pdf-files-using-read-pdf-activity). So what method of extraction does this activity use? I know it’s not OCR. There’s a different activity for it. So is it what I think it is–the FullText method? I tried extracting data from the pdf using both the activities, and I found out that the Read PDF Text activity is way faster. And I don’t know if it extracts hidden text, too, but if it does, does it mean my assumption is correct or are there no such methods involved in simple extraction (or scraping)?