See http://cr.openjdk.java.net/~jjg/java-javafx-jdk-docs/api/overview-summary.html - "description" column in the overview page is empty for these modules:
jdk.charsets
jdk.httpserver
jdk.localedata
jdk.naming
jdk.net
jdk.pack
jdk.rmic
jdk.unsupported
jdk.zipfs
jdk.sctp