The web browser plugin calls it
It probably uses the same channel as what the epic games launcher uses.
it’s inside
FWebBrowserSingleton::FWebBrowserSingleton(const FWebBrowserInitSettings& WebBrowserInitSettings){ // code }
So a singleton that handles web browsing by Unreal.
Maybe the experimental Web Socket Messaging could be used to replace the web browser?
You could also try closing it directly if there is public access to the functions
