Examine source code of OneNote Web Clipper

{
  "manifest_version": 2,
  "name": "OneNote Web Clipper",
  "description": "__MSG_appDesc__",
  "default_locale": "en",
  "version": "3.9.5",
  "background": {
    "scripts": [
      "firefoxExtension.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://onenote.officeapps.live.com/*",
        "https://ppc-onenote.officeapps.live.com/*",
        "https://onenote.officeapps-df.live.com/*",
        "https://onenote.officeapps.live-int.com/*"
      ],
      "js": [
        "appendIsInstalledMarker.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "web_accessible_resources": [
    "clipper.html",
    "pageNav.html"
  ],
  "permissions": [
    "<all_urls>",
    "activeTab",
    "contextMenus",
    "tabs",
    "webRequest",
    "storage",
    "webNavigation"
  ],
  "applications": {
    "gecko": {
      "id": "Clipper@OneNote.com",
      "strict_min_version": "48.0"
    }
  },
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "browser_action": {
    "default_title": "Clip to OneNote",
    "default_icon": {
      "19": "icons/icon-19.png",
      "38": "icons/icon-38.png"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "19": "icons/icon-19.png",
    "32": "icons/icon-32.png",
    "38": "icons/icon-38.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png",
    "256": "icons/icon-256.png"
  }
}