Examine source code of POE TradeNinja

{
  "manifest_version": 2,
  "name": "POE TradeNinja",
  "version": "1.0.3",
  "icons": {
    "16": "icons/icon_16x16.png",
    "48": "icons/icon_48x48.png",
    "128": "icons/icon_128x128.png",
    "256": "icons/icon_256x256.png",
    "512": "icons/icon_512x512.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/icon_16x16.png",
      "24": "icons/icon_32x32.png",
      "32": "icons/icon_32x32.png"
    },
    "default_popup": "popup/popup.html"
  },
  "description": "Adds a Trade button to items in Path of Exile build pages and handles the trading process.",
  "permissions": [
    "storage",
    "cookies",
    "https://poe.ninja/builds/*/character/*",
    "https://www.pathofexile.com/trade/search/*",
    "https://www.pathofexile.com/api/trade/data/stats",
    "https://www.pathofexile.com/*",
    "https://pathofexile.com/*"
  ],
  "background": {
    "scripts": [
      "background/background.js"
    ],
    "persistent": true
  },
  "content_security_policy": "script-src 'self'; object-src 'self';",
  "content_scripts": [
    {
      "matches": [
        "https://poe.ninja/builds/*/character/*"
      ],
      "js": [
        "content/poeninja/content.js"
      ],
      "css": [
        "content/poeninja/style.css"
      ]
    },
    {
      "matches": [
        "https://www.pathofexile.com/trade/search/*"
      ],
      "js": [
        "content/pathofexile/content.js"
      ],
      "css": [
        "content/pathofexile/style.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ca769dc5-39ad-4351-a8a3-108ddc84f4d8}"
    }
  }
}