Version 5.x has been out of support since December 13, 2022, and this corresponding section of the documentation is no longer maintained. We strongly recommend you upgrade to the latest supported version of 7.x and read the latest version of this documentation.
The discovery endpoint can be used to retrieve metadata about your IdentityServer - it returns information like the issuer name, key material, supported scopes etc.
The discovery endpoint is available via /.well-known/openid-configuration relative to the base address, e.g.:
https://demo.duendesoftware.com/.well-known/openid-configuration
You can use the IdentityModel client library to programmatically interact with the protocol endpoint from .NET code.
var client = new HttpClient();
var disco = await client.GetDiscoveryDocumentAsync("https://demo.duendesoftware.com");