Can GPUAdapterInfo reliably indicate a fallback adapter in WebGPU?

Context

WebGPU’s requestAdapter accepts a forceFallbackAdapter flag that asks the implementation to return a non‑hardware backend, typically a software rasterizer. The API does not mandate which backend is used, and the GPUAdapterInfo fields are populated at the implementation’s discretion.

Unresolved behavior

Because the selection is implementation‑defined, the same page can resolve to different adapters across browsers, operating systems, and GPU blocklist states. There is no documented mapping from forceFallbackAdapter:true to a specific backend name, and the stability of vendor, architecture, device, and description fields remains unclear.

Questions

• Which concrete backend (e.g., “swiftshader”, “fossil”, “software rasterizer”) is returned when forceFallbackAdapter:true is requested in current browsers?
• How consistent are the GPUAdapterInfo fields across browsers and platform configurations when a fallback adapter is selected?
• Is there a reliable runtime pattern to detect a fallback adapter without relying on hard‑coded field values?