Examine source code of Visa Notify

{
  "name": "Visa Notify",
  "description": "An extension that notifies latest visa interview dates! developed by Jasbin Karki",
  "version": "1.4.2",
  "manifest_version": 2,
  "icons": {
    "16": "/images/bell_16.png",
    "32": "/images/bell_32.png",
    "48": "/images/bell_48.png",
    "128": "/images/bell_128.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/bell_16.png",
      "32": "images/bell_32.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://cgifederal.secure.force.com/ApplicantHome",
        "https://cgifederal.secure.force.com/applicanthome"
      ],
      "js": [
        "js/content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "background": {
    "scripts": [
      "js/background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "activeTab",
    "storage",
    "notifications",
    "cookies",
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "visanotifyv1.4.0@jasbin.com.np",
      "strict_min_version": "90.0"
    }
  }
}