This is a structured approach to mapping a problem domain before you design anything. It's all about capturing how people think and talk about their work now, not how your product will work later. The discipline is resisting the urge to resolve conflicts: if two groups call the same thing by different names, or use the same word to mean different things, that's data about where your conceptual model will need to make choices. You get a toolkit of techniques like concept mapping, terminology audits, and noun harvests that feed directly into building your conceptual model. Most useful when you're entering a complex domain you don't fully understand yet.
npx skills add https://github.com/jamiemill/layers-skills --skill layers-domain