Claude Opus 4.6 holds #1 and #2 on Arena in both reasoning modes. GPT-5.4 ranks 6th at high and 14th at default. What are ChatGPT Plus users actually getting?

Arena lists gpt-5.4 and gpt-5.4-high as separate entries with a big ranking gap between them. OpenAI hasn't said what reasoning level Plus users get by default or what Extended/Heavy maps to. Meanwhile both Claude variants are top 2 and available to every subscriber. Does anyone know the actual mapping?