Edit: Found another copy, converted to raw images. This copy contains correct Disk3, Disk15 and Disk27. (Yeah, the previous copy has corrupted disks)
Download: https://mega.nz/#!B0xlkDwI!ENRAFrqes-zX ... BXfbegCyys
Windows 3.1 Chinese Edition DDK(5.25'',Extension Pack): https://mega.nz/#!xlgXSIRY!ML1TH4B-sUud ... MWnf3aqYVI
It came with 27 DiskDupe images originally and has been converted to raw images.
Compared to Darkstar's copy:
Disk18 = Online Documentation 1
Disk19 = Online Documentation 2
Disk20 = Online Documentation 3
Disk21 = Online Documentation 4
Disk22 = Device Driver Samples & Tools
Disk content all matches.