Examine source code of Override NewTab

{
  "name": "Override NewTab",
  "description": "Override NewTab with html file",
  "version": "1.0.0",
  "icons": {
    "16": "icons/icon16.png",
    "19": "icons/icon19.png",
    "38": "icons/icon38.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_action": {
    "default_icon": "icons/icon48.png"
  },
  "content_security_policy": "script-src 'self'; img-src *; style-src 'unsafe-inline'; default-src 'self';",
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{abed11ce-8022-4759-b1e2-895f502674de}"
    }
  }
}