using Newtonsoft.Json; using NJsonSchema; using System.Collections.Generic; // Load JSON schema var schema = JsonSchema.FromFileAsync("schema.json").Result; // Get extra namespaces var extraNamespaces = schema.GetExtraNamespaces();In this example, we use the JsonSchema.FromFileAsync method to load a JSON schema from a file. Then, we use the GetExtraNamespaces method to get a list of extra namespaces defined in the schema. The package library for JsonSchema4 is "NJsonSchema".