MITRE ATT&CK
A knowledge base of adversary tactics and techniques. Use it to find detection gaps, not to decorate a slide.
ATT&CK is a matrix of tactics (the goal) and techniques (the method). Defenders map telemetry and detections onto it to see coverage and holes.
A heatmap produced once for a board pack is interior design. A living map tied to detections you run is engineering.
Stay at technique level unless you are a detection engineer. This site does not document how to perform the techniques.