The Kong OIDC plugin is an OpenID Connect Relying Party (RP) implementation for the Kong API gateway. It authenticates users against an OpenID Connect Provider using the Authorization Code flow and supports token introspection for Bearer tokens. The plugin maintains user sessions and adds headers (X-Userinfo, X-Access-Token, X-ID-Token) to the upstream request for use by backend services. The plugin follows a modular architecture with separate modules for handling the main logic (handler.lua), request filtering (filter.lua), session configuration (session.lua), and utility functions (utils.lua). It relies on the `lua-resty-openidc` library for the core OIDC protocol handling. Key features include configurable session storage (client-side cookie or server-side via shared memory, memcache, or Redis), caching of discovery documents and access tokens, and support for both authentication and token introspection modes. Note: This repository is not maintained and is not recommended for use in production, as indicated in the README. The last commit history shows no recent activity, and dependencies are outdated relative to current Kong and OIDC library versions.