anyone know how to debug chrome extention independently (not using google chrome)

[Mendax47]

I am recently doing some experiments with Grammarly google chrome extension. you can bypass the premium popup because this popup is not server-side. at the first time login, it receives some JSON which includes your subscription plan, and use it to restrict your membership.. but the main problem is I can't find the exact main root when it first store the JSON object as a javascript object in the window object and read it from there... so I need a good debugger.