# ETAF Playground The Playground exposes one canonical product example: the `examples/research-shelf.etaf` and `examples/research-shelf.el` pair. The `.etaf` file is inert, validated structural composition data. The same- basename companion owns Components, state, theme, storage, events, and lifecycle. `etaf-playground.el` is a reusable pair framework: it owns only registration, safe loading, mounting, reset, close, and verification entry points. `etaf-playground-catalog.el` is the replaceable deployment catalog; business Components, database schemas, palettes, refs, and handlers must stay in the companion. Compose and reuse public ETAF/`etaf-ui` contracts before adding abstractions. Run `make check EMACS=/Applications/Emacs.app/Contents/MacOS/Emacs`. Run `make perf` for the 1413×62 warm row-selection/theme latency gate.