Here are the packages with brief descriptions (if available):

[detail level 12345]

com
rti	RTI
connext	RTI Connext Messaging communication patterns
requestreply	Support for the request-reply communication pattern
ndds	DDS extensions
example	Programming HowTos: Code templates for common use cases
config	Utility API's independent of the DDS standard
transport	APIs related to RTI Connext pluggable transports
dds	DDS
domain	Contains the com.rti.dds.domain.DomainParticipant class that acts as an entrypoint of RTI Connext and acts as a factory for many of the classes. The com.rti.dds.domain.DomainParticipant also acts as a container for the other objects that make up RTI Connext
builtin	Builtin topic for accessing information about the DomainParticipants discovered by RTI Connext
dynamicdata	<<eXtension>> The Dynamic Data API provides a way to interact with arbitrarily complex data types at runtime without the need for code generation
infrastructure	Defines the abstract classes and the interfaces that are refined by the other modules. Contains common definitions such as return codes, status values, and QoS policies
publication	Contains the com.rti.dds.publication.FlowController, com.rti.dds.publication.Publisher, and com.rti.dds.publication.DataWriter classes as well as the com.rti.dds.publication.PublisherListener and com.rti.dds.publication.DataWriterListener interfaces, and more generally, all that is needed on the publication side
builtin	Builtin topic for accessing information about the Publications discovered by RTI Connext
subscription	Contains the com.rti.dds.subscription.Subscriber, com.rti.dds.subscription.DataReader, com.rti.dds.subscription.ReadCondition, and com.rti.dds.subscription.QueryCondition classes, as well as the com.rti.dds.subscription.SubscriberListener and com.rti.dds.subscription.DataReaderListener interfaces, and more generally, all that is needed on the subscription side
builtin	Builtin topic for accessing information about the Subscriptions discovered by RTI Connext
topic	Contains the com.rti.dds.topic.Topic, com.rti.dds.topic.ContentFilteredTopic, and com.rti.dds.topic.MultiTopic classes, the com.rti.dds.topic.TopicListener interface, and more generally, all that is needed by an application to define com.rti.dds.topic.Topic objects and attach QoS policies to them
builtin	Builtin topic for accessing information about the Topics discovered by RTI Connext
type
builtin	<<eXtension>> RTI Connext provides a set of very simple data types for you to use with the topics in your application
typecode	<<eXtension>> A com.rti.dds.typecode.TypeCode is a mechanism for representing a type at runtime. RTI Connext can use type codes to send type definitions on the network. You will need to understand this API in order to use the Dynamic Data capability or to inspect the type information you receive from remote readers and writers
util	Utility types that support the DDS API