I need to think more about this one. It's a bit of a violation of @pika/pack's whole deal to copy the source code directly into the package (or at least, every package so far has tried to just build modern ES2020 code into it instead). But I also see that this is a great use case for including the src/ directory, or at least having an option to include it.

I was thinking about this during the past few days. The declarationMap setting should be false by default, but tsconfig.json could override it. When the latter approach is taken, the src directory must be copied to the resulting package.