lib_beamdeconv does not exist?

https://git.astron.nl/RD/rapthor/-/blob/master/rapthor/lib/image.py#L184

In rapthor/lib/image.py an import is made

from lib_beamdeconv import deconvolve_ell, EllipticalGaussian2DKernel

but I don't see this in the Rapthor source code or as a dependency. Do we know where this comes from?