Examine source code of Steam Browser

{
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "steam-browser@seano.dev"
    }
  },
  "name": "Steam Browser",
  "version": "1.0.1",
  "description": "Directly open pages from Steam on your browser in the desktop app with the single click of a button.",
  "author": "Sean O'Connor",
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": [
      "steam-browser.min.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "16": "/assets/steam-gray16.png",
      "32": "/assets/steam-gray32.png"
    }
  },
  "icons": {
    "48": "/assets/steam48.png",
    "96": "/assets/steam96.png",
    "128": "/assets/steam128.png"
  }
}