Examine source code of SeqN+copy

{
  "manifest_version": 2,
  "name": "SeqN+copy",
  "version": "1.0.1",
  "description": "__MSG_app_description__",
  "default_locale": "ja",
  "browser_action": {
    "default_title": "SeqN+copy"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ae63df66-c6ad-4ad4-9e63-5befd990388e}"
    }
  },
  "permissions": [
    "storage"
  ],
  "background": {
    "scripts": [
      "/event.js"
    ],
    "persistent": false
  },
  "icons": {
    "16": "/img/icon16.png",
    "32": "/img/icon32.png",
    "48": "/img/icon48.png",
    "128": "/img/icon128.png"
  }
}