A-Frame <a-assets> timeout permits scene startup while entities render untextured

When an asset within <a-assets> exceeds its timeout threshold, A-Frame proceeds with scene initialization regardless of the asset's load status. This investigation aims to clarify whether entities referencing the timed-out asset receive a deterministic rendering state or remain in an undefined visual condition.

The timeout attribute's default and supported values have changed across A-Frame releases, and cross-origin assets require explicit crossorigin handling. Additionally, a timed-out asset does not schedule a subsequent load attempt, which may lead developers to assume incorrect consistency for subsequent renders.

Does A-Frame emit a per-asset timeout event that identifies the originating entity? Is the scene's loaded event reliably deferred until all non-timed-out assets finish loading? Can developers depend on a stable API to detect which assets triggered a timeout without custom instrumentation?