Examine source code of Words Counter

{
  "name": "Words Counter",
  "short_name": "WordsCounter",
  "version": "0.1.0",
  "description": "__MSG_extDescription__",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "default_locale": "en",
  "browser_action": {
    "default_title": "__MSG_extName__",
    "default_icon": {
      "16": "res/icons/logo_16.png",
      "48": "res/icons/logo_48.png",
      "128": "res/icons/logo_128.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "js/contentScript.js"
      ],
      "all_frames": true,
      "run_at": "document_start"
    }
  ],
  "icons": {
    "16": "res/icons/logo_16.png",
    "48": "res/icons/logo_48.png",
    "128": "res/icons/logo_128.png"
  },
  "permissions": [
    "contextMenus"
  ],
  "author": "Oziku Technologies LLC",
  "browser_specific_settings": {
    "gecko": {
      "id": "{3b4ede00-c462-47e6-8a15-fc699959c320}"
    }
  }
}