Explanation

This section covers "why", not "how". If you are trying to finish a job, How-to will be quicker; this is for the decisions and the boundaries.

Page	What it covers
Concepts	Feature, group, scale, pipeline — the basic structure
What NaN means	Why a number is missing, and why that is good
The verification system	What ✅ 🟡 🔍 ❌ ⚪ ⚫ 🔧 mean and how to read them
Limitations	Where not to trust it