Examine source code of zeppter

{
  "manifest_version": 2,
  "name": "zeppter",
  "version": "1.0",
  "description": "zeppter online book store",
  "homepage_url": "https://www.zeppter.com/",
  "icons": {
    "48": "icons/zeppter.png"
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/zeppter.png"
    }
  },
  "background": {
    "scripts": [
      "zeppter.js"
    ]
  }
}