Examine source code of Force Safe Search

{
  "manifest_version": 2,
  "name": "Force Safe Search",
  "author": "Bill Hayden",
  "version": "1.6",
  "description": "Force Safe Search on all major search engines: Google, YouTube, Yahoo, Bing, Yandex, Dogpile, Reddit, Ixquick, and DuckDuckGo",
  "icons": {
    "44": "icon44.png",
    "50": "icon50.png",
    "128": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "all_frames": true,
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "background": {
    "page": "background.html",
    "persistent": true
  },
  "permissions": [
    "<all_urls>",
    "webRequest",
    "webRequestBlocking",
    "cookies",
    "nativeMessaging"
  ],
  "-ms-preload": {
    "backgroundScript": "backgroundScriptsAPIBridge.js",
    "contentScript": "contentScriptsAPIBridge.js"
  }
}