Examine source code of Hebrew Calendar

{
  "manifest_version": 2,
  "name": "Hebrew Calendar",
  "version": "1.3",
  "description": "A Hebrew-Gregorian calendar extension",
  "default_locale": "en",
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "permissions": [
    "storage"
  ],
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{fdad0595-0016-4223-bc82-d2b6aa3e8d48}"
    }
  }
}