FS Endianess

[Sam]

Hi,

I am under the assumption that a Filesystem created on big endian
machine cant be read on little endian machine and vice versa. However
I am able to mount FAT formatted(on Windows PC) USB flash drive on
FreeBSD(PowerPC - BigEndian) and able to view contents of a text file.
I am not able to locate FS code where it does the byte conversion. Can
somebody kindly point me the code? Or my assumption is wrong?

Thanks
Samuel