Examine source code of ePub Creator

{
  "manifest_version": 2,
  "name": "ePub Creator",
  "short_name": "ePub Creator",
  "version": "0.5.7",
  "author": "Niklas Gollenstede",
  "description": "Create offline e-books from web pages and 'overdrive.com' with a single click on the icon.",
  "icons": {
    "1": "/icon.svg"
  },
  "minimum_chrome_version": "55.0.0",
  "applications": {
    "gecko": {
      "id": "@epub",
      "strict_min_version": "59.0"
    }
  },
  "permissions": [
    "storage",
    "notifications",
    "sessions",
    "activeTab",
    "<all_urls>"
  ],
  "optional_permissions": [],
  "web_accessible_resources": [],
  "incognito": "spanning",
  "background": {
    "page": "node_modules/web-ext-utils/loader/_background.html",
    "persistent": true
  },
  "options_ui": {
    "page": "ePub#options",
    "open_in_tab": false
  },
  "browser_action": {
    "default_icon": {
      "1": "/icon.svg"
    },
    "default_title": "Save as ePub"
  },
  "homepage_url": "https://github.com/NiklasGollenstede/epub-creator#readme"
}