Examine source code of Xposer

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "version": "4.0.2",
  "icons": {
    "16": "/icons/16-icon-default.png",
    "32": "/icons/32-icon-default.png",
    "48": "/icons/48-icon-default.png",
    "128": "/icons/128-icon-default.png"
  },
  "author": "Michiel Roos <xposer.free.bra@michielroos.com>",
  "homepage_url": "https://www.michielroos.com/",
  "default_locale": "en",
  "permissions": [
    "activeTab",
    "storage",
    "https://www.xposer.io/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Xposer",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7bbe5150-d23e-4882-83e0-f228147ceb13}"
    }
  }
}