The PapxInFkp structure specifies a set of text properties.
cb (1 byte): An unsigned integer that specifies the size of the grpprlInPapx. If this value is not 0, the grpprlInPapx is 2×cb-1 bytes long. If this value is 0, the size is specified by the first byte of grpprlInPapx.
grpprlInPapx (variable): If cb is 0, the first byte of grpprlInPapx (call it cb') is an unsigned integer that specifies the size of the rest of grpprlInPapx. cb' MUST be at least 1. After cb', there are 2×cb' more bytes in grpprlInPapx. The bytes after cb' form a GrpPrlAndIstd.
If cb is nonzero, grpprlInPapx is GrpPrlAndIstd.