Examine source code of AppointmentCore Inbox Plugin

{
  "manifest_version": 2,
  "name": "AppointmentCore Inbox Plugin",
  "version": "0.11",
  "default_locale": "en",
  "icons": {
    "16": "./assets/img/appcore16.png",
    "32": "./assets/img/appcore32.png",
    "48": "./assets/img/appcore48.png",
    "128": "./assets/img/appcore128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://mail.google.com/*",
        "http://mail.google.com/*",
        "https://outlook.office.com/*",
        "http://outlook.office.com/*",
        "https://outlook.office365.com/*",
        "http://outlook.office365.com/*",
        "https://outlook.live.com/*",
        "http://outlook.live.com/*"
      ],
      "js": [
        "plugin/parser.js",
        "plugin/observer.js",
        "plugin/element.js",
        "plugin/clickable-element.js",
        "plugin/button.js",
        "plugin/icon-button.js",
        "plugin/frame.js",
        "plugin/icon.js",
        "plugin/app-injector.js",
        "plugin/plugin.js",
        "main.js"
      ],
      "css": [
        "styles.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "web_accessible_resources": [
    "assets/img/appcore_calendar_black.svg",
    "assets/img/appcore_calendar_white.svg"
  ],
  "permissions": []
}