Examine source code of Steam Inventory Manager

{
  "manifest_version": 2,
  "name": "Steam Inventory Manager",
  "version": "1.0",
  "description": "A simple tool to help manage your Steam inventory items.",
  "permissions": [
    "tabs",
    "activeTab",
    "https://steamcommunity.com/*"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "default_title": "Steam Inventory Manager"
  },
  "content_scripts": [
    {
      "matches": [
        "https://steamcommunity.com/id/*/inventory*",
        "https://steamcommunity.com/profiles/*/inventory*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{9af54b63-9d7b-4a01-a3ea-8a6887b0b0cc}"
    }
  }
}