Examine source code of ViewerJS WE

{
  "description": "__MSG_appDesc__",
  "manifest_version": 3,
  "name": "__MSG_appName__",
  "version": "1.4.2",
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "{b514ad55-4cab-41e0-9141-9f8d00373d93}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "strict_min_version": "140.0"
    }
  },
  "icons": {
    "16": "odt-16.png",
    "32": "odt-32.png",
    "64": "odt-64.png",
    "96": "odt-96.png",
    "128": "odt-128.png"
  },
  "action": {
    "default_icon": {
      "16": "odt-16.png",
      "32": "odt-32.png",
      "64": "odt-64.png"
    }
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "tabs",
    "notifications",
    "menus",
    "storage"
  ],
  "host_permissions": [
    "http://*/*",
    "https://*/*"
  ],
  "background": {
    "scripts": [
      "content-disposition.js",
      "bg.js"
    ]
  },
  "web_accessible_resources": [
    {
      "resources": [
        "images/*.png",
        "index.html"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ]
    }
  ]
}