What's open sourced here is the design kit. Designed chips need to be sent to IHP to be manufactured.
SiGe isn't also that useful for military radar applications. Compared to SiGe GaN has much greater breakdown voltage which leads to greater output power and better efficiency. It's possible to get 10 to 100 times more output power from GaN chip compared to SiGe. It isn't really possible to make high performance long range radar with just SiGe although it could be used in some parts of it.
SiGe isn't also that useful for military radar applications. Compared to SiGe GaN has much greater breakdown voltage which leads to greater output power and better efficiency. It's possible to get 10 to 100 times more output power from GaN chip compared to SiGe. It isn't really possible to make high performance long range radar with just SiGe although it could be used in some parts of it.