The description of undertow subsystem is: A deployment
Steps to reproduce:
- Deploy an application, e.g. the logging quickstart
- Click Deployments -> deployment name -> View -> expand subsystem -> undertow
Other subsystems have better description, for example logging subsystem:
Information about the logging configuration for this deployment. Note that this may not be accurate if the deployment is using some other means of configuring a log manager such as logback. The resolved configuration is what loggers not covered by the deployments specific log manager would use.