Examine source code of URL Filter

{
  "manifest_version": 2,
  "name": "URL Filter",
  "description": "Automatically close tabs whose URLs match any user-defined regex patterns",
  "version": "1.0",
  "icons": {
    "32": "icon/32.png",
    "64": "icon/64.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": "icon/64.png",
    "default_title": "URL Filter",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e52e64d3-ce14-4280-899c-7c101012cc27}",
      "strict_min_version": "92.0"
    }
  }
}