Underscore syntax and anonymous modules?

So I can’t do module _ end? Is that still consistent with “syntax requires a variable but the variable is never used”? It would be useful in creating different namespaces.

No. See Anonymous or temporary module syntax · Issue #40189 · JuliaLang/julia · GitHub — you can do

@eval Module() begin
    # put code here

to have an anonymous module.

See also How do you make anonymous module w/ variables?