Examine source code of Universal Edit Button

{
  "manifest_version": 2,
  "name": "Universal Edit Button",
  "description": "Show a button for editable web pages and wikis",
  "version": "2.0.2resigned1",
  "author": "Andreas Gohr",
  "homepage_url": "http://universaleditbutton.org",
  "background": {
    "persistent": false,
    "scripts": [
      "background.js"
    ]
  },
  "page_action": {
    "default_icon": {
      "16": "skin/wiki-16.png",
      "19": "skin/wiki-19.png",
      "24": "skin/wiki-24.png",
      "32": "skin/wiki-32.png",
      "38": "skin/wiki-38.png",
      "48": "skin/wiki-48.png"
    },
    "default_title": ""
  },
  "content_scripts": [
    {
      "matches": [
        "https://*/*",
        "http://*/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "permissions": [
    "tabs",
    "http://*/*",
    "https://*/*"
  ],
  "icons": {
    "16": "skin/wiki-16.png",
    "24": "skin/wiki-24.png",
    "32": "skin/wiki-32.png",
    "48": "skin/wiki-48.png",
    "96": "skin/wiki-96.png",
    "128": "skin/wiki-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "button@wikihow.com"
    }
  }
}