IBM RTC 6.0.2: Develop extensions on WEBSPHERE 8.5.5
One answer
I suppose you're talking about WebSphere Liberty profiles? The default Liberty server.xml, or the one comes with the "clm" profile bundled in CLM, does not have all the available elements. If you need it, just add it. Note that for the CLM Liberty profile, the <application> element is in the application.xml file. You should also be aware of some limitations of applications in the dropins folder.
http://www.ibm.com/support/knowledgecenter/SSEQTP_8.5.5/com.ibm.websphere.wlp.doc/ae/twlp_setup_dyn_upd.html
http://www.ibm.com/support/knowledgecenter/SSAW57_8.5.5/com.ibm.websphere.wlp.nd.doc/ae/twlp_sec_rolebased.html