With Java9/Jigsaw a new entity is introduced: the module name.
In case a jar has a module-info.class, the name can be extracted from this content.
In case there's no module-info.class, there's a strategy to extract the name based on the filename.
http://cr.openjdk.java.net/~mr/jigsaw/spec/api/java/lang/module/ModuleFinder.html#of-java.nio.file.Path...- should help in detecting the name.
Nexus is probably one of those application used by developers trying to discover the modulename for any jar.