The model is named Apertus – Latin for “open” – highlighting its distinctive feature: the entire development process, including its architecture, model weights, training data and methods, is openly accessible and fully documented.

https://ethz.ch/en/news-and-events/eth-news/news/2025/09/press-release-apertus-a-fully-open-transparent-multilingual-language-model.html

There is also a move into synthetic data and human trained so we will have to see where the training data goes copyright wise in the future