This package is part of Robot OS (ROS). It is mainly used to find client libraries (via 'rospack depends-on1 roslang'). The roslang package is only of interest to those implementing a ROS client library. Client libraries mark themselves as such by depending on the roslang package, which allows rosbuild and other tools to perform appropriate actions, such as msg- and srv-based code generation. The roslang package itself contains no actual code.