What are ‘open weights’ in A.I.? When technologists refer to open weights, they mean that the calculations, or rules, governing the A.I. Hardcore proponents of open-source software say open-weights models still do not go far enough in sharing information. Since then, China has become the source of most of the world’s leading open-source models, including from companies like Alibaba, Z.ai and Moonshot AI. China’s strength in open-source A.I.