Examine source code of Close Tabs By Pattern

{
  "author": "Mathieu Pillard",
  "background": {
    "scripts": [
      "main.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "close-tabs-by-pattern@virgule.net",
      "strict_min_version": "57.0"
    }
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": "icon.svg",
    "default_title": "Close Tabs By Pattern"
  },
  "description": "Automatically close tabs whose URL match specific patterns",
  "homepage_url": "https://github.com/diox/close-tabs-by-pattern/",
  "manifest_version": 2,
  "name": "Close Tabs By Pattern",
  "options_ui": {
    "browser_style": true,
    "page": "options.html"
  },
  "permissions": [
    "<all_urls>",
    "storage",
    "tabs"
  ],
  "version": "0.2"
}