Currently, in our How to configure server security guide, there is a section 2.2.5. Removing Undertow Response Headers.

Because of recent changes in default configuration in undertow subsystem - WFLY-9000, this section is gonna be obsolete with upcoming EAP7.2 release.

We should either remove this section completely. Or change its name and update it with some general information how such headers may disclose information about server in use... I think that removing this section should be okay.