Examine source code of Steam Player Counts

{
  "manifest_version": 2,
  "name": "Steam – Live Player Counts for Games",
  "version": "1.0.0",
  "description": "View current player counts for Steam games",
  "permissions": [
    "activeTab",
    "https://store.steampowered.com/*",
    "https://europe-west1-steam-player-stats.cloudfunctions.net/*"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon16.png",
      "24": "icon24.png",
      "32": "icon32.png",
      "48": "icon48.png",
      "64": "icon64.png",
      "96": "icon96.png",
      "128": "icon128.png",
      "256": "icon256.png"
    }
  },
  "icons": {
    "16": "icon16.png",
    "24": "icon24.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "64": "icon64.png",
    "96": "icon96.png",
    "128": "icon128.png",
    "256": "icon256.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "steam-player-stats@example.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}