correctly in your Blender Asset Browser.
The file "EEVEE-Cycles-Materials-V9.1" is part of the created by Chipp Walters . This system is a popular library for Blender designed to provide photorealistic materials that work seamlessly in both the EEVEE and Cycles render engines. Key Details of the Material System
Most materials are designed to be applied without requiring complex UV unwrapping.
V9.1 is an older release; the system has since been updated to V9.3 and beyond.
for photorealistic materials (like AmbientCG or PolyHaven). Configure EEVEE settings to match Cycles-level realism. EEVEE + Cycles Materials System - chippwalters
Official versions are sold on Blender Market and Gumroad.