Examine source code of MxDetect

{
  "description": "Detects if the website you are visiting is a Mendix App.",
  "manifest_version": 2,
  "name": "MxDetect",
  "version": "0.1",
  "homepage_url": "https://github.com/pommi/MxDetect",
  "icons": {
    "48": "icons/mendix-logo.svg"
  },
  "permissions": [
    "activeTab",
    "webRequest",
    "webNavigation"
  ],
  "browser_action": {
    "default_icon": "icons/mendix-logo-grey.svg",
    "default_title": "MxDetect"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}