In the page above, developers can hover on one application, there is an arrow which points downward on the top right conner of the app card. Click that arrow and then either resign or delete the application depend on which are the current roles of the accounts.
Alternatively you can put it back into the sandbox mode - which isn't so easy to find either (it's in the App Review section), so I put a current location screenshot here:
I followed the steps mentioned before but for some reason when clicking on the app it will take you to the analytics page.
To go to the actual app page from your apps you can click on the bell and then Setting -> Advanced -> Remove App at the bottom, or faster, click on the three dots and then Remove App