Examine source code of Container Picker

{
  "manifest_version": 3,
  "name": "Container Redirect",
  "version": "1.4.2",
  "description": "Pick a Firefox container whenever you navigate to a watched domain.",
  "browser_specific_settings": {
    "gecko": {
      "id": "container-redirect@example.local",
      "strict_min_version": "115.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "contextualIdentities",
    "cookies",
    "webRequest",
    "webRequestBlocking",
    "webNavigation",
    "tabs",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_popup": "popup.html",
    "default_title": "Container Redirect",
    "default_icon": {
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "96": "icons/icon-96.png"
    }
  },
  "icons": {
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "icons.js",
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "run_at": "document_idle",
      "all_frames": false
    }
  ]
}