Agreed with the site hospitality, those popup was added yesterday on demand by users form https://www.producthunt.com/tech/data-scraping-studio to collect the leads for OS X and API interested users and prioritize accordingly. Will remove after 2-3 days.

Chrome app documentation is available here : http://www.datascraping.co/doc/39/chrome-extension It was just in Help center > Documentation

If you've installed the Chrome app, it will automatically take you to the tutorial.