Debugging Box Missing

Hi there. The debugging feature on my edit page seems to have disappeared. It used to be under my set featured image box, and when an image wasnt the right size it would turn pink and say ‘debug this’. Now my featured images aren’t showing up on my shares AND the debugging box is gone. I tried the plug in “Debug This’ but didnt understand it, its all code, which im not really that experienced with.I deleted several plug ins recently to address other issues ive been having, but nothing I thought would have been related to this. Isnt debugging a built in feature of WordPress? Do I need a plug in? Thanks for any advice anyone can provide!

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