To successfully extract the "interesting guide" inside, you will need all parts of the archive (parts 1, 2, and any subsequent pieces) in the same folder before opening part 1 with a utility like WinRAR or 7-Zip. Do you have the other parts of this archive, or CONTRACT DATA REQUIREMENTS LIST - acq.osd.mil

The filename is likely part of a segmented archive containing a technical guide or manual, specifically related to a Contract Data Requirements List (CDRL) .

: Program documentation or source code requirements. Project Management : Status reports and administrative data. Why the File is Split into Parts