Examine source code of Steam Redirect

{
  "manifest_version": 2,
  "name": "Steam Redirect",
  "version": "1.0",
  "description": "steamcommunity.com automatically redirects to the Steam app.",
  "icons": {
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://steamcommunity.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{454a1346-619e-4bd8-a9ec-3cf638c91333}"
    }
  }
}