I plan to use Keycloak to secure my Mule REST APIs, but I'm not sure which adapter I can use for integration. As per Keycloak documentation, "Keycloak can be secured by supplied adapters that are usually easier to use and provide better integration with Keycloak. However, if an adapter is not available for your programming language, framework, or platform you might opt to use a generic OpenID Connect Resource Provider (RP) library instead." What exactly is meant by "generic OpenID Connect Resource Provider (RP) library"?
This sentence (in the Keycloak Securing Applications and Services Guide) is incorrect. "OpenID Connect Resource Provider (RP) library" means "OpenID Connect Relying Party (RP) library" such as mod_auth_openidc , and you can see the libraries on this page.