Examine source code of Custom Search Engine

{
  "name": "Custom Search Engine",
  "short_name": "Custom Search Engine",
  "description": "To use, type 'ms' plus keyword for custom search engines & search term into the url bar. (e.g. ms google <search text>).",
  "version": "1.7resigned1",
  "manifest_version": 2,
  "icons": {
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "applications": {
    "gecko": {
      "id": "custom-search-engine@rsins.addons.mozilla.org",
      "strict_min_version": "52.0a1"
    }
  },
  "background": {
    "scripts": [
      "utils.js",
      "browser-polyfill.min.js",
      "background.js"
    ]
  },
  "omnibox": {
    "keyword": "ms"
  },
  "permissions": [
    "https://raw.githubusercontent.com/rsins/ravi-firefox-custom-search-engines/master/SampleCustomEngines/PopularSearchEngines.txt",
    "storage"
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  }
}