It is covered in the blog post if you read it. https://web.archive.org/web/20200120104750/https:/www.elastic.co/what-is/open-x-pack https://web.archive.org/web

It is covered in the blog post if you read it. https://web.archive.org/web/20200120104750/https:/www.elastic.co/what-is/open-x-pack https://web.archive.org/web/20200120104750/https:/www.elasti... "We did not change the license of any of the Apache 2.0 code of Elasticsearch, Kibana, Beats, and Logstash — and we never will."