With current build of JBoss EAP 7.4.0.Beta-CR1, we can see following difference of docs/schema/wildfly-undertow_10_0.xsd schema since JBoss EAP 7.3.0 release:
$ diff -u /tmp/jboss-eap-7.3/docs/schema/wildfly-undertow_10_0.xsd wildfly-undertow_10_0.xsd
--- /tmp/jboss-eap-7.3/docs/schema/wildfly-undertow_10_0.xsd 2020-11-20 10:20:06.000000000 +0100
+++ wildfly-undertow_10_0.xsd 2021-02-03 08:34:56.000000000 +0100
@@ -19,9 +19,12 @@
+ <xs:import namespace="urn:wildfly:credential-reference:1.0" schemaLocation="wildfly-credential-reference_1_0.xsd"/>
<!-- The undertow subsystem root element -->
<xs:element name="subsystem" type="undertow-subsystemType"/>
This change has been introduced by this commit that fixed
WFLY-13369 (or WFLY-12510 effectively).
If I understand correctly, based on the discussion in
WFLY-12510, the wildfly-undertow_10_0.xsd schema should not been updated at all since it was already present in WildFly 19 release. With this change it was updated and is served with current content till now, see:
$ find . -name "wildfly-undertow_10*.xsd" | xargs md5sum
To be honest - I am not sure how serious this problem is since effectively there is no functional change in the XSD schema definition - complex types that are brought in by added credential-reference:1.0 dependency schema are already part of the wildfly-undertow_10_0.xsd file. Although, from the customer point of view this change between 7.3.0 and 7.4.0 may be confusing at least.
Note: Correct value of `Affects Version/s` for this issue should be 7.4.0.Beta-CR1, although there is no such option at the moment.