Examine source code of Claude Usage Meter

{
  "manifest_version": 2,
  "name": "Claude Usage Meter",
  "version": "1.0.0",
  "description": "Real-time session & weekly usage bars, token counter, and cache timer for claude.ai",
  "browser_specific_settings": {
    "gecko": {
      "id": "claude-usage-meter@extension",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  },
  "permissions": [
    "storage",
    "https://claude.ai/*"
  ],
  "background": {
    "scripts": [
      "src/background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "https://claude.ai/*"
      ],
      "js": [
        "src/vendor/o200k_base.js",
        "src/content/constants.js",
        "src/content/bridge-client.js",
        "src/content/tokens.js",
        "src/content/ui.js",
        "src/content/main.js"
      ],
      "css": [
        "src/styles.css"
      ],
      "run_at": "document_idle",
      "all_frames": false
    }
  ],
  "web_accessible_resources": [
    "src/injected/bridge.js",
    "src/vendor/o200k_base.js"
  ],
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  }
}