Examine source code of Image Website Saver

{
  "author": "igorlogius",
  "homepage_url": "https://github.com/igorlogius/save-website-as-image",
  "background": {
    "scripts": [
      "jszip.js",
      "background.js"
    ]
  },
  "browser_action": {
    "default_area": "navbar",
    "theme_icons": [
      {
        "light": "dark.png",
        "dark": "icon.png",
        "size": 128
      }
    ]
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Alt+S"
      }
    }
  },
  "icons": {
    "128": "icon.png"
  },
  "manifest_version": 2,
  "name": "Image Website Saver",
  "description": "Simple addon, to save a snapshot of a website via a click on the toolbar icon or a custom shortcut",
  "permissions": [
    "storage",
    "tabs",
    "<all_urls>"
  ],
  "options_ui": {
    "page": "options.html"
  },
  "version": "1.4.25",
  "browser_specific_settings": {
    "gecko": {
      "id": "{dd09158f-c20d-43d4-aac2-0f89c36fee82}"
    }
  }
}