Number of UCS-2 characters that fit in a VFAT LFN. Note that FAT doesn’t support the full range of Unicode characters (UCS-2 is only 16 bits), and short file names can’t encode the full 16-bit range of UCS-2. This is the minimum possible value. For instance, a 300 byte UTF-8 string could fit inside 255 UCS-2 codepoints (if it had some 16 bit characters), but a 300 byte ASCII string would not fit.