Role Based Access Control is a widely spread concept in cyber security. Thus, the (NP-complete) Role Mining Problem (RMP), which consists of finding an optimal set of roles and a corresponding assignment of those roles to users, is of great scientific interest. Over the last years, different algorithms have been developed to search for good solutions to the RMP. However, conclusive benchmarks for thorough comparison of the developed methods are rarely known. This paper introduces to RMPlib, a library for the Role Mining Problem, containing a set of new industry-oriented benchmark instances partly taken from real-world use cases, partly created synthetically. Access to RMPlib is provided through a platform where researchers can actively contribute new benchmark instances and best solutions, such that the library adapts to the changing requirements in science. The current version of RMPlib can be found at https://github.com/RMPlib/RMPlib.