CSV data files are commonly used as data exchange files for numerous uses, even for storing vectors and coordinates that can be used for using embroidery/stitching designs for example. This is actually what csv to phb conversion represents, making Brother ULT embroidery designs (.phb) based on CSV format.
Of course .phb is often a typo for .php or even other formats, so you might have been searching for something entirely different.
Updated: November 3, 2023