This is PageFly - Free Landing Page Builder. The code happened because the page was built by PageFly old version. You can delete it easily by this way: Come to your Shopify dashboard > Online store > Theme > Open Edit code - theme.liquid. Find this code below and delete it.
Because you didn't provide URL, I couldn't find your store name on our list. In case you can not find it, please don't hesitate to chat with ourLive chat. We havesupport team 24/7to help customer solve their problems.