Rio de Janeiro's "homegrown" LLM appears to be a merge of an existing model
Rio-3.5-Open-397B's weights are a direct element-wise merge of Nex with Qwen3.5-397B-A17B at roughly 0.6/0.4, with no evidence of independent training. Every weight tensor across a…
straightforward model forensics. the authors demonstrate weight interpolation through statistical analysis and behavioral testing—when you strip the system prompt, the model identifies itself as Nex. …