Examine source code of Steam Search

{
  "manifest_version": 2,
  "name": "Steam Search",
  "description": "Searches highlighted text on Steam",
  "version": "1.0",
  "permissions": [
    "menus"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "icon_16.png",
    "48": "icon_48.png",
    "128": "icon_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f5c51df0-7231-4755-b45b-7ce3cb10b63e}"
    }
  }
}