Examine source code of XKCD Alt Text Display

{
  "manifest_version": 2,
  "name": "XKCD Alt Text Display",
  "version": "2.0",
  "description": "Displays the alt text below the XKCD comic.",
  "icons": {
    "48": "icons/icon_48.png",
    "96": "icons/icon_96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.xkcd.com/*"
      ],
      "js": [
        "xkcdAltTextDisplay.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{9413b005-3c1d-4cf9-927f-628546db16b3}"
    }
  }
}