Examine source code of O365 Templater

{
  "manifest_version": 2,
  "name": "O365 Templater",
  "version": "1.0.0",
  "description": "Vytváření a správa HTML šablon a podpisů pro Outlook Web",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "storage",
    "activeTab",
    "tabs",
    "https://outlook.office.com/*",
    "https://outlook.office365.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "https://outlook.office.com/*",
        "https://outlook.office365.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "O365 Templater"
  },
  "options_page": "options.html",
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "browser_specific_settings": {
    "gecko": {
      "id": "{c4c879d8-7be3-405d-bc60-98a394cab584}"
    }
  }
}