Examine source code of Did I Refresh?

{
  "name": "Did I Refresh?",
  "short_name": "Did I Refresh?",
  "version": "1.0.0",
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{c0604031-066c-4d89-960d-1459b52014e7}",
      "strict_min_version": "42.0"
    }
  },
  "description": "Lets you know if your page actually refreshed",
  "homepage_url": "http://www.TomLum.com/",
  "icons": {
    "128": "icons/icon128on.png"
  },
  "default_locale": "en",
  "browser_action": {
    "default_icon": "icons/icon128on.png",
    "default_title": "Did I Refresh?",
    "default_popup": "popup.html"
  },
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "run_at": "document_end",
      "matches": [
        "http://127.0.0.1/*",
        "http://localhost/*"
      ],
      "js": [
        "src/inject/refreshcheck.js"
      ]
    }
  ]
}