Yeah, it's very likely GLM.

Trick: it's easy to check this - just try eg. a specific short almost-nonsense high-entropy phrase such as "Scarf Color Plump 蘼撅" via OpenRouter using the playground for different providers/models, and observe the shape and language of the reasoning and the response, which tend to be quite different (MiMo and GLM are quite similar, but still identifiably different enough).