Is there any way to inspect which modules are included in a dynamic library product build using SPM?

So want to create a dynamic swift library containing multiple modules. In my Package.swift it looks like this:

    name: "MyLib",
    type: .dynamic, 
    targets: [

I'm able to build this product just fine with swift build --product MyLib, however when I try to link against it, I get the following error:

error: missing required module 'Cmyctarget'

This is when I try to build and link manually using swiftc:

swiftc -swiftc -I. -L. -lMyLib foo.swift

So I have tried to reproduce this in the simplest possible case, and it seems like it's not reproducible. I'm at a bit of a loss trying to figure out how to debug this, so I am wondering:

  1. is there any way to get information about which modules are contained in a dynamic library build using SPM? It would be extremely helpful if I could take a look at the contents of my .so as it's viewed by SwiftC to try to understand where the problem is occuring..

  2. How are the interfaces defined for a dynamic library containing multiple modules? In a C project, I would expect to have an include directory somewhere with all the header files which would have to be included in the -I argument for the compiler. But what's the equivalent here? Do I have to include the include paths from my C language source directories individually, or does that get sorted out somehow by the compiler?