In short, Amber is a programming language with Rust like syntax that compiles down to bash. More details here: https://amber-lang.com/
On the surface, it seems nice. Cleaner syntax, types, compile-time safety checks, etc. So you get to write in something nicer than bash but get the portability of bash.
My wonder is if there are pitfalls that make it worse than instead writing it in something like Python or even bash itself. I’d guess the generated bash code probably isn’t the prettiest to look at or debug.
They mention in the FAQ that they currently require some features of Bash but are thinking about including POSIX sh as a possible target. My guess without investigating is that they are using a thing like arrays that make implementation way easier but is not technically POSOX sh.