For some plugins, it can be useful to automatically modify or extend the TiddlyWeb configuration. This can be achieved using an init function within the plugin module, which is passed the config variable.

For example, the following code automatically inserts the necesary configuration for the CSS serializer:
def init(config):
    # automatically extend configuration
    content_type = "text/css"
    config["extension_types"]["css"] = content_type
    config["serializers"][content_type] = [__name__, "text/css; charset=UTF-8"] })

(Note the use of __name__ to refer to the plugin module itself.)