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BiRefNet is the default backend and --seg-backend switches segmenters, so the birefnet.yaml config (a copy of default.yaml with backend: birefnet) no longer had a purpose. configs/ now holds just default.yaml, the editable parameter template. Also dropped the now-redundant --config from the chroma-debug README example. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>