Remove that line from the JSON file.
Here’s a draft review for enabling debug mode in Project Zomboid Build 42. You can post this on Steam, Reddit, or a forum. How to enable debug mode in Project Zomboid Build 42 (tested & working) how to enable debug mode project zomboid build 42
Debug mode can cause unexpected behavior or crashes in Build 42 – it’s an unstable build. Backup your saves first. Works as of the latest B42 patch. Remove that line from the JSON file