Contains packages for modeling various aspects of robot information, specified in the Xml Robot Description Format (URDF). The core package of this stack is urdf, which parses URDF files, and constructs an object model (C++) of the robot.
ROS communications-related packages, including core client libraries (roscpp, rospy, roslisp) and graph introspection tools (rostopic, rosnode, rosservice, rosparam).
Standalone Python library for generating ROS message and service data structures for various languages
Provides a standardized interface for interfacing with preemptable tasks. Examples of this include moving the base to a target location, performing a laser scan and returning the resulting point cloud, detecting the handle of a door, etc.
Allows one to create "nodelets" -- ROS node-like entities that run within the same process so as to avoid IPC and serialization overhead