Description of `Specular Tint` may be not clear enough - Documentation - Developer Forum
Specular Shaders — Blender Manual
The Principled BSDF Shader in Blender | Brandon's Drawings
How to get sharp reflections but rough transmission with the new 4.0 shaders? : r/blenderhelp
BSDF Principled Hair — Blender Manual
BSDF Principled — Blender Manual
Is it possible to get specular color in cycles? principled doesn't accept color in the specular input and specular bsdf renders as black in cycles. : r/blender