EAR file: jars in archive root vs library folder?

I'm looking at an existing JEE enterprise app (EAR) that has a number of application and third-party JAR files located in the archive root ("/"), as well as a WAR module and a JBoss SAR module. There are also a much smaller set in the library folder ("/lib"). I understand the role of the library folder (sharing classes between modules), but it's not clear what the significance of putting JAR files in the root would be.

Is there some kind of distinction in classloaders (e.g. root JARs go into a single classloader shared by all modules but JARs in /lib load into each module's dedicated CL)?