I've compared the list of elements in the "Chapter 48. Configuration Reference" with xml file of hornetq-configuration.xsd from HQ trunk and found out that there are some elements, i.e. configuration properties, that does not have any description in the docs.

A. There is a list of elements that are not documented anywhere in the HornetQ User Guide:
initial-wait-timeout
log-delegate-factory-class-name
live-connector-ref
log-journal-write-rate
perf-blast-pages
run-sync-speed-test
server-dump-interval
connector-services
connector-services.connector-service
bridges.ha
bridges.user
bridges.password
bridges.static-connectors
cluster-connections.static-connectors
message-counter-history-day-limit

B. There is a list of elements documented in the HornetQ User Guide, but not enlisted in the Chapter 48.1.1.:
allow-failback
failover-on-shutdown
shared-store
grouping-handler
remoting-interceptors
address-full-policy
send-to-dla-on-no-route

All those elements are related to hornetq-configuration.xml.