Examine source code of QueueNary - Smart Queue Tracking

{
  "manifest_version": 3,
  "name": "QueueNary",
  "version": "0.9.0",
  "description": "Track Walmart and Pokémon Center queues from your own tabs, see local wait outlooks, and get notified when it's your turn.",
  "browser_specific_settings": {
    "gecko": {
      "id": "getqueuenary@gmail.com",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "storage",
    "notifications",
    "alarms"
  ],
  "host_permissions": [
    "https://*.walmart.com/*",
    "https://*.pokemoncenter.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_title": "QueueNary — open queue dashboard",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png"
    }
  },
  "sidebar_action": {
    "default_title": "QueueNary",
    "default_panel": "dashboard.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png"
    },
    "open_at_install": false
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.walmart.com/*"
      ],
      "js": [
        "capture.js"
      ],
      "run_at": "document_start",
      "world": "MAIN"
    },
    {
      "matches": [
        "https://*.walmart.com/*",
        "https://*.pokemoncenter.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ]
}