SSS?

PBR?

how do those guide me to do something or use these whatever?

drawn

Procedural SSS = Procedural Subsurface Scatter

This skin shader is based on Snarlgribbly's EZSkin Python script that generates subsurface scatter skin textures for Firefly and Superfly rendering.  Although imperfect, it can generate better skin textures for most models with a figure definition, and they can be created by the users.  In this case, someone generated an EZSkin shader for L'Homme and included it with his material package.

PBR = Physically Based Rendering

PBR depends on material room nodes and lighting optimized to create a photorealistic Superfly render.