It constitutes a C library to compute the frenet conversion.
It furthermore contains the definition of the frenet conversion service, which is instead at <race_stack folder>/f110_utils/nodes/frenet_conversion_server.
An example of the usage of the frenet conversion library can be seen in the Frenet Odometry Republisher. It basically imports the library in the header file (<race_stack folder>/f110_utils/nodes/frenet_odom_republisher/include/frenet_odom_republisher_node.h, line 11) then it instantiates the converter object in line 32.
TODO: We should write a wrapper/version of the converter in python