Licenses ZIP for 3.15.1.ER1 contains two licenses, which according to the licences.xml file are related to artifact xpp3 and are not found in https://git.app.eng.bos.redhat.com/git/jboss-licenses.git/plain/rh_license_list.json list:
1. "Apache Software License, version 1.1" (there is "Apache Software License 1.1" in the list, but we need to be sure, this is the same one)
2. "Indiana University Extreme! Lab Software License, vesion 1.1.1" (there is "Indiana University Extreme! Lab Software License Version 1.1.1" in the list, without the typo). Also there is no text of the license, the file in contents folders contains phrase "This site has been deprecated. You can access an archive of this site at [an URL at archive.org]" instead.