Catznip is the development viewer for RLVa. This is an extended reimplementation of the original RestrainedLove API created by Marine Kelley. RLVa is independent and shares no code with the original RLV. (See RLVa / RLV Differences).
RLVa goes from Catznip into many other viewers making it especially useful for script developers as it represents the future of RLVa often months ahead of the mainstream.