3D Gaussian Blur: How is it calculated?


I’m trying to understand how the 3D Gaussian Blur filter works in ImageJ. I have read the documentation but I don’t fully understands it.

According to Wikipedia and Scipy (Python Library for Image processing), in order to generate a 3D kernel of a gaussian one ways is to generate 3 consecutive 1D kernels.
Is this the way the 3D Gaussian Blur works in ImageJ?