Examine source code of Extractos Destacados

{
  "manifest_version": 2,
  "name": "Extractos Destacados",
  "version": "1.0",
  "description": "Permite seleccionar texto, resaltarlo y guardarlo para futura referencia.",
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "activeTab",
    "scripting",
    "storage",
    "contextMenus"
  ],
  "browser_action": {
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png"
    },
    "default_title": "Gestionar Extractos Destacados",
    "default_popup": "popup/popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{090ca81a-13d8-442f-b98d-7a434b74a0ed}"
    }
  }
}