This issue is purely informational, you do not need to take any action. Thank you for your work maintaining docbook5-style-xsl in EPEL 10. Red Hat considers this package important enough to promote it to official RHEL. It will be part of RHEL 10.0. Please do not update docbook5-style-xsl in EPEL 10 so the RHEL version can have a higher version and release. When RHEL 10.0 is released, EPEL automation will remove docbook5-style-xsl from EPEL 10 and close this bug.
Verified that package is in RHEL 10.0. Package has been retired from epel10 and epel10.0. It might take a few days before it is cleared from the repositories and mirrors.