Examine source code of Show YouTube Upload Date

{
  "manifest_version": 2,
  "name": "Show YouTube Upload Date",
  "version": "2.5",
  "description": "Shows upload date of YouTube video, regardless of window size.",
  "icons": {
    "16": "/icons/icon-16.png",
    "32": "/icons/icon-32.png",
    "48": "/icons/icon-48.png",
    "128": "/icons/icon-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*"
      ],
      "js": [
        "ShowYouTubeUpload.js"
      ]
    }
  ],
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "{f17ca885-e688-47a2-b62c-e2cf11d19ba5}"
    }
  }
}