lazy = true in the settings makes the generated main module register the members of each package on its first use instead of at import.
First use is an attribute access, dir(), a star import, or a C++ object of that package crossing into Python.
Types, enums, exceptions and submodules of every package are still created at import; the first commit arranges that, so a class is complete before its members are added later.

pywrap only emits the package table and the call; the C++ that defers the registration (lazy::desc, lazy::install) lives in the wrapped project's include_pre header.
Without the option the generated code is unchanged.

Tested: this allows import OCP to go from 0.79s to 0.16s once OCP is adjusted on its side.