There is one log warning message which is not properly internationalized in Wildfly 'xts' submodule:
./src/xts/src/main/java/org/jboss/as/xts/GracefulShutdownRejectionRule.java:45: XTSLogger.logger.warnf("rejecting call because it is not part of any XTS transaction")
All logs of level WARN and higher should be internationalized.

The message needs to be added to XTS in JBossTS and then xts module modified to use it.