Common Data Format
The Common Data Format (CDF) is a file format and associated APIs designed by NASA for multi-dimensional datasets. It has largely been supplanted by the (mostly unrelated, except in name) netCDF.
The version 3 examples start with byte sequence
CD F3 00 01, the middle ranged versions (2.6 and 2.7) begin with
CD F2 60 02 and
older versions 2.5 or earlier start with byte sequence
00 00 FF FF.