Thanks so much for sharing these files! However, perhaps I'm missing something (if so, my apologies), but I don't see the connection between the zip file names to anything mentioned in the PDF above.
I'm looking for the files for my 2017 Legacy (head unit FB876US), which should be MY17_LEG_OUT NAVI #1 (containing C_NU9511_USB_1st.exe) and MY17_LEG_OUT NAVI #2 (containing C_NU9511_USB_2nd.exe).
Which zip files would they be?