Ok, you do have the correct idea… That it was supposed to create a set of measurements originally, but I think that part of it was scrapped a while back.
What it does do, is it changes the names of the different measurement areas according to the different books you choose there. I have no idea whether it does this in any other language than English.
I can understand that this isn’t important for someone who does know how to make patterns before they discover the program, but I can assure you, for someone like me who only discovered pattern making AFTER discovering the program, it was like gold 