Logback supports -Dlogback.debug=true to figure out where a running system is getting its logback.xml file.

Similarly, SLF4J should support -Dslf4j.debug=true to figure out how it's determining which logging implementation to use.

For mere mortals using slf4J-logback on an application server such as WildFly, Tomcat, Websphere, Weblogic, ... it can be extremely difficult to figure out where their logging configuration is coming from. This would make it easy.

Optional: -Dslf4j.debug implies -Dlogback.debug, so 1 system property is enough to figure out where the logging configuration comes from.