HLSL
Writing Shader Code in Universal RP (v2)
Explains how shader code (ShaderLab & HLSL) is written to support the Universal RP
Intro to Shaders
An introduction to what a Mesh, Shader and Material is in Unity, how to set Shader Properties from C#, a brief look at Forward vs Deferred rendering and some information about Material instances and Batching

Depth
A big post explaining everything about Depth : Depth Buffer, Depth Texture / Scene Depth node, SV_Depth, Reconstructing World Position from Depth, etc.