The numpy.linalg module depends on LAPACK, which is Fortran.

Core numpy depends on BLAS, for which both Fortran and non-Fortran implementations are available.

Go to the source, it's called lapacklite and it's C code translated from Fortran

https://github.com/numpy/numpy/tree/master/numpy/linalg

Hmm, seems you're right. Though that seems to be some fallback thing which is used if the real thing isn't found during the build. At least on Ubuntu 16.04 the lapack_lite module links against the real (Fortran) lapack library:

  % ldd /usr/lib/python3/dist-packages/numpy/linalg/lapack_lite.cpython-35m-x86_64-linux-gnu.so|grep -E 'lapack|fortran'
	liblapack.so.3 => /usr/lib/liblapack.so.3 (0x00007fb619ce7000)
	libgfortran.so.3 => /usr/lib/x86_64-linux-gnu/libgfortran.so.3 (0x00007f5ae0911000)