The SMESH python package contains (today) helper functions to manipulate mesh elements and interact with these elements.
Note that these functions either encapsulate the python programming interface of SMESH core (the CORBA or SWIG interface for example) or extend existing utilities as the smesh.py module.
The functions are distributed in the python package salome.smesh.
The specification of the programming interface of this package is detailled in the part Documentation of the programming interface (API) of this documentation.
Note
The main package salome contains other sub-packages that are distributed with the other SALOME modules. For example, the KERNEL module provides the python package salome.kernel and GEOM the package salome.geom.