Examine source code of Buff Currency Converter

{
  "manifest_version": 2,
  "name": "Buff Currency Converter",
  "version": "1.2",
  "description": "Change the listing currency on 163.buff.com",
  "permissions": [
    "alarms",
    "storage",
    "*://buff.163.com/*"
  ],
  "background": {
    "scripts": [
      "src/background.js"
    ]
  },
  "browser_action": {
    "default_title": "Preferences",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "assets/icon16.png",
    "48": "assets/icon48.png",
    "128": "assets/icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://buff.163.com/*"
      ],
      "run_at": "document_idle",
      "js": [
        "src/content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{fbb6684e-9172-4a59-b55b-39c9b69ffb74}"
    }
  }
}