Looks like a 5.56 in progress. Supposedly gonna be a similar design to a AR180 with a quick change barrel. There has been a tangible prototype since at least January that had stanag m16 flavored magazines. There will be a good article coming out on it soon from a very popular firearm blog institution. Stay tuned!
https://www.spartanat.com/2021/05/es-kommt-das-glock-sturmgewehr/
https://www.spartanat.com/2021/05/es-kommt-das-glock-sturmgewehr/