Examine source code of Hijri Cal

{
  "manifest_version": 2,
  "name": "Hijri Cal",
  "description": "Simple hijri calendar, now with calendar variants, arabic support and moon phase.",
  "version": "2.0",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "96": "icon/96.png",
    "128": "icon/128.png",
    "512": "icon/512.png"
  },
  "permissions": [
    "storage"
  ],
  "commands": {
    "_execute_action": {
      "suggested_key": {
        "default": "Ctrl+H",
        "mac": "Command+H"
      },
      "description": "Open the popup"
    }
  },
  "browser_action": {
    "default_title": "Hijri Cal",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a6b9b66a-1ade-4756-88e0-dae2decc7504}"
    }
  }
}