Examine source code of Hiddenpost

{
  "version": "18.1.22resigned1",
  "manifest_version": 2,
  "name": "Hiddenpost",
  "short_name": "Hiddenpost",
  "description": "__MSG_appDesc__",
  "homepage_url": "https://www.hiddenpost.com/",
  "default_locale": "en",
  "icons": {
    "16": "icon/icon16.png",
    "32": "icon/icon32.png",
    "48": "icon/icon48.png",
    "128": "icon/icon128.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "action/icon16.png",
      "20": "action/icon20.png",
      "24": "action/icon24.png",
      "25": "action/icon25.png",
      "30": "action/icon30.png",
      "32": "action/icon32.png",
      "40": "action/icon40.png",
      "48": "action/icon48.png"
    },
    "default_popup": "index.htm"
  },
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{91ffc0da-db4b-431e-a3ac-4033337c692c}"
    }
  }
}