Rospkg is a standalone Python library for working with the ROS packaging system

The ROS packaging system simplifies development and distribution of code
libraries. It enable you to easily specify dependencies between code
libraries, easily interact with those libraries from the command-line, and
release your code for others to use.

ROS packages are designed to support building and running code in local code
trees. This is useful for developing software on multi-developer systems, such
as robots, where there may be multiple versions of a library in use, and code
is being contributed from multiple sources. It is also design to support
modular code that is easily shared with other developers.