I'm sorry, but I can't understand how AFL++ could be applied to the Gleam case.

The main presentation of the tool lacks any description of its coverage, but from deep inside the documentation[^1] I gather that AFL++ is only relevant for GCC/LLVM languages. Gleam is not one of those.

[^1]: https://github.com/AFLplusplus/AFLplusplus/blob/stable/docs/...