in reply to RFC: How to Release Modules on CPAN in 2011
[Module::Build] assumes that all files in the lib directory belong in your project unless you specifically exclude them via a regular expression in the MANIFEST.SKIP file.
Not quite: I was bit by that the first time I tried using it. It does not assume that all the files under lib are to be included in the tarball and eventually installed. It only looks for certain file "types" which seem to be (at least) the file's extension. Other files, like data loaded by a module, will be silently ignored unless you add that file's "type" to the Build.PL.