Examine source code of claude-usage-gauge

{
  "manifest_version": 2,
  "name": "Claude Usage Tracker",
  "version": "3.1.0",
  "description": "Affiche la vraie jauge d'utilisation Claude (session 5h + hebdo 7j) dans les conversations.",
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/icon48.png"
    },
    "default_popup": "popup.html",
    "default_title": "Claude Usage Tracker"
  },
  "content_scripts": [
    {
      "matches": [
        "*://claude.ai/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "gauge.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "storage",
    "tabs",
    "*://claude.ai/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "claude-usage-tracker@extension",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}