Examine source code of Tumblr Unrecommend

{
  "manifest_version": 2,
  "name": "Tumblr Unrecommend",
  "version": "1.2resigned1",
  "description": "Remove \"recommended\" posts from your Tumblr dashboard.",
  "icons": {
    "48": "icon-48.png",
    "96": "icon-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.tumblr.com/*"
      ],
      "css": [
        "unrecommend.css"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{5acd6d30-0c49-4a68-a8b3-aaee58e990d3}"
    }
  }
}