tl;dr We might need a standard build file to build a module from Git repository, especially for the ones using Module::Install or dzil.
When an author of CPAN module uses an authoring tool that generates build files when shipping them to CPAN, the git repository usually doesn't have enough files to build, test and install the module.
For example, if dzil (Dist::Zilla) is used, the repository only conatains dist.ini
and there's no Makefile.PL
or Build.PL
so standard CPAN installers or Continuous Integration tools don't know how to run tests on it.