Examine source code of Codenames-Revealer

{
  "manifest_version": 2,
  "name": "Codenames-Revealer",
  "version": "1.0",
  "description": "Reveals the hidden cards by listening to websocket traffic - codenames.game",
  "icons": {
    "64": "icons/hat_colorful.png"
  },
  "permissions": [
    "<all_urls>",
    "tabs"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.codenames.game/*"
      ],
      "all_frames": true,
      "run_at": "document_end",
      "js": [
        "content.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "socket-sniffer.js"
  ],
  "browser_action": {
    "browser_style": true,
    "default_popup": "popup/popup.html",
    "default_icon": {
      "48": "icons/hat_colorful.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{af7cefd9-43cc-4aba-b1c1-e8fc6b44e47d}"
    }
  }
}