They are talking about two different systems. Static compilation is a separate project which is trying to include only those compiled code that is required. That isn't ready yet for normal people like me, but if you have the knowhow and your program meets certain requirements you can get a tiny binary.

PackageCompiler.jl just compiles everything and packages it up. It generates huge files, because it doesn't discriminate on which compiled stuff to include.

I see, thanks. Looks like static compilation will only work if the entire program is “type stable”, which AFAICT means that the type of every variable can be deduced statically.