Hey, I worked on pre-training data Kolibri. We spent considerable time and effort to go beyond just translating. For example by building a pipeline that processes Common Crawl dumps specifically for German. You might be interested in a related blog post: https://aleph-alpha.com/en/blog/sauerkraut-not-burgers-why-g...

We also talk more about German pre-training data in the tech report: https://aleph-alpha.com/downloads/tech-report.pdf section 2.3.2.2.