Examine source code of Beyond Metric

{
  "name": "Beyond Metric",
  "short_name": "BM",
  "description": "An extension for dndbeyond that converts the measurements on the website in the metric system using Matthew Roy's method.",
  "version": "1.0.0",
  "icons": {
    "128": "images/logo.png"
  },
  "manifest_version": 2,
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "github@r2pi.net",
      "strict_min_version": "57.0"
    }
  },
  "content_scripts": [
    {
      "run_at": "document_end",
      "matches": [
        "*://www.dndbeyond.com/*characters/*"
      ],
      "js": [
        "scripts/Utils.js",
        "scripts/CharacterSheet.js"
      ]
    },
    {
      "run_at": "document_end",
      "matches": [
        "*://www.dndbeyond.com/monsters/*"
      ],
      "js": [
        "scripts/Utils.js",
        "scripts/MonsterStats.js"
      ]
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "images/logo.png"
  }
}