Searching for the source code of function `LinearNDInterpolator` in SciPy

Question

I am trying to examine the function LinearNDInterpolator invoked in the following Python code

from scipy.interpolate.interpnd import LinearNDInterpolator

I came to the SciPy GitHub branch scipy/scipy/interpolate but can not find 'interpnd' much less LinearNDInterpolator. The function scipy/scipy/interpolate/ndgriddata.py uses the function LinearNDInterpolator. I suspect this is because interpnd is not a Python script but something like C++ or even Fortran that Python is wrapping around. Is this the case?

Answer 1

Looks like it's written in Cython.
Source code link