dh_numpy3 adds information about the correct versioned depends on python3-numpy to python3:Depends
substvar.
This is needed because some Python extensions require strict versioned depends on python3-numpy, and
using this helper script is the easiest and most consistent way to get them.
The helper script uses the information stored in /usr/share/numpy3/versions, and the architecture type of
the package, to generate the Depends information; for a detailed description of how the dependencies are
generated, please refer to /usr/share/doc/python3-numpy/README.DebianMaints .