Examine source code of Simple Word Counter Plus

{
  "manifest_version": 2,
  "name": "__MSG_extName__",
  "version": "12.1.1",
  "description": "__MSG_extDescription__",
  "default_locale": "en",
  "permissions": [
    "storage",
    "https://clients2.google.com/service/update2/crx"
  ],
  "options_page": "options.html",
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/icon16.png",
      "48": "images/icon48.png",
      "128": "images/icon128.png"
    }
  },
  "icons": {
    "16": "images/icon16.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "exclude_matches": [
        "*://mail.google.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles.css"
      ]
    }
  ],
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "web_accessible_resources": [
    "test.html",
    "images/icon16.png",
    "images/icon48.png",
    "images/icon128.png",
    "content.js",
    "styles.css",
    "options.html",
    "popup.html"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{96dd760b-c3ce-4875-9050-c46a1c5b8a74}"
    }
  }
}