rostopic contains the rostopic command-line tool for displaying debug information about ROS<a href="http://wiki.ros.org/Topics">Topics</a>, including publishers, subscribers, publishing rate, and ROS<a href="http://wiki.ros.org/Messages">Messages</a>. It also contains an experimental Python library for getting information about and interacting with topics dynamically. This library is for internal-use only as the code API may change, though it does provide examples of how to implement dynamic subscription and publication behaviors in ROS.