The astropy-helpers package includes many build, installation, and documentation-related tools used by the Astropy project, but packaged separately for use by other projects that wish to leverage this work. The motivation behind this package and details of its implementation are in the accepted Astropy Proposal for Enhancement (APE) 4.
Astropy-helpers is not a traditional package in the sense that it is not
intended to be installed directly by users or developers. Instead, it is meant
to be accessed when the setup.py command is run - see the
"Using astropy-helpers in a package"
section in the documentation for how to do this.
For a real-life example of how to implement astropy-helpers in a
project, see the setup.py and setup.cfg files of the
Affiliated package template.
For more information, see the documentation at http://astropy-helpers.readthedocs.io