I'm interested in more information regarding the Safe Systems Programming Languages team's work. Did they assess other languages other than Rust? I'm scanning t

I'm interested in more information regarding the Safe Systems Programming Languages team's work. Did they assess other languages other than Rust? I'm scanning through their blog entries, without having read every single one in depth so please pardon me if I miss something, and I'm not seeing anything mentioning formal methods or other systems programming languages. It's a very interesting development for sure!