Mysterious “gpt2-chatbot” AI model appears suddenly, confuses experts

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On Sunday, word began to spread on social media about a new mystery chatbot named "gpt2-chatbot" that appeared in the LMSYS Chatbot Arena. Some people speculate that it may be a secret test version of OpenAI's upcoming GPT-4.5 or GPT-5 large language model (LLM). The paid version of ChatGPT is currently powered by GPT-4 Turbo.

Currently, the new model is only available for use through the Chatbot Arena website, although in a limited way. In...