Examine source code of Tab Closer

{
  "manifest_version": 3,
  "name": "Tab Closer",
  "version": "1.0",
  "description": "A simple extension to close tabs with specified URL",
  "permissions": [
    "tabs",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "bd50ad775783f9c27bad1bbe671936484d8f8a62@signaturesolutionsjsc.online"
    }
  }
}