I may be missing something, but how is POD not for breaking down the implementations of a module and using it successfully? When I go to read how to use a module I have not seen before, I read the documentation of it.

POD (and user-facing documentation in general) is for describing the purpose and usage of modules and their functions. It is not, in general cases, for describing the internal ways the module achieves its ends as these are very rarely any concern of the user.

For each function/sub/method one could reasonably expect the documentation to include:

• function name
• Arguments: types, names/positions, optional/mandatory, defaults, acceptable values
• Return values: types, names/positions, flag values
• Conditions which will throw exceptions
• Prose describing the purpose, side-effects, caveats, context-sensitive matters, etc.
• Example(s) showing how to call the function with suitable arguments, etc.

In other words, everything to do with the purpose of the call and the interface to it. Everything else internal to the function does not need documenting here (eg. private variables, other functions it calls, etc.).