Product page showing meta info

https://premadebusiness.com/products-page/ready-made-businesses/facebook-business-model-2/

As you can see there it shows at the end

layout_key: f
post_slider_check_key: 0

Any idea what this is? I have deleted the fields that contain the layout key and post slider but they re-appear.

[ Please do not bump, that’s not permitted here. ]