Examine source code of Transit Trip Stitcher

{
  "manifest_version": 3,
  "name": "Transit Trip Stitcher",
  "version": "1.5",
  "description": "Chain public transit legs in a single tab.",
  "permissions": [
    "storage"
  ],
  "icons": {
    "128": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "transit-stitcher@example.com",
      "strict_min_version": "109.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.google.com/maps*",
        "*://maps.google.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ]
}