looks like might be a WIP Mirror Cut SubDs (symmetry)
I’m going through the install info and this is really confusing imo: “File > Special Folders > Components Folder (The folder it actually opens will be called LIBRARIES, not Components, DO NOT PUT PUFFERFISH IN THE FOLDER ACTUALLY CALLED COMPONENTS).” 
at any rate this might be what I’m missing, “5. For installing the Pufferfish WIP SubD Components, Open Grasshopper in Rhino 7 and go to File > Special Folders > User Objects Folder, place the files from the “Pufferfish WIP SubD Components” folder into that User Objects Folder.” …