Examine source code of Regex Tab Closer

{
  "manifest_version": 2,
  "name": "Regex Tab Closer",
  "version": "1.2",
  "description": "Instantly close multiple browser tabs using the power of regular expressions. Match by URL or title to clean up your workspace in seconds.",
  "icons": {
    "48": "icons/icon-48.png"
  },
  "browser_action": {
    "default_icon": "icons/icon-48.png",
    "default_title": "Regex Tab Closer",
    "default_popup": "popup.html"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{40aaac77-c1e9-4d7d-afcc-40ee0b5e145e}"
    }
  }
}