Examine source code of Maps 24-Hour Clock

{
  "manifest_version": 2,
  "name": "Maps 24-Hour Clock",
  "version": "1.0.0",
  "description": "Converts AM/PM times on Google Maps to 24-hour format — no more mental math.",
  "author": "maps24hclock",
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.google.com/maps*",
        "*://maps.google.com/*",
        "*://google.com/maps*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "maps24hclock@extension",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}