Examine source code of OutlineKit: CSS Layout Outliner

{
  "manifest_version" : 3 ,
  "name" : "OutlineKit: CSS Layout Outliner",
  "short_name" : "OutlineKit",
  "version" : "1.2.0",
  "description" : "See every box on a page: clean outlines by depth or tag, hover labels, spacing view. Pro: layout report.",
  "icons" : {
    "16" : "icons/icon16.png",
    "32" : "icons/icon32.png",
    "48" : "icons/icon48.png",
    "128" : "icons/icon128.png"
  },
  "action" : {
    "default_title" : "OutlineKit (Alt+Shift+O toggles outlines)",
    "default_popup" : "popup.html",
    "default_icon" : {
      "16" : "icons/icon16.png",
      "32" : "icons/icon32.png"
    }
  },
  "background" : {
    "scripts" : [
      "config.js" ,
      "lib/core.js" ,
      "lib/licence.js" ,
      "background.js" 
    ]
  },
  "permissions" : [
    "activeTab" ,
    "scripting" ,
    "storage" 
  ],
  "optional_host_permissions" : [
    "https://*/*" ,
    "http://*/*" 
  ],
  "commands" : {
    "toggle-outlines": {
      "suggested_key": {
        "default": "Alt+Shift+O"
      },
      "description" : "Turn outlines on or off on this tab"
    },
    "toggle-labels": {
      "suggested_key": {
        "default": "Alt+Shift+L"
      },
      "description" : "Turn hover labels on or off"
    }
  },
  "homepage_url" : "https://digivibetech.com/outlinekit/",
  "browser_specific_settings": {
    "gecko": {
      "id": "outlinekit@digivibetech",
      "strict_min_version": "128.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}