A configuration item that can be in tiddlywebconfig.py. It serves two purposes:

It is used to start up the included server, if used, on a chosen host and port.
It is used to properly create fully qualified ~URLs even when operating behind a proxy or on a private IP.

It is a dict with the following structure:

    'server_host': {
        'scheme': 'http', # or https
        'host': 'tiddlyweb.peermore.com', # or an IP number
        'port': '80', # or some other port. You must put port even if 80 or 443. This needs to be a string.
    }

The defaults are http, '0.0.0.0' and '8080'. If you are planning to access your TiddlyWeb server from machines other than the one the server is running on, you will need to update the host portion so it refers to an externally addressable hostname of IP.