A .KSC files contains a list of KMP files (multisamples) - normally to be used by your own programs - and/or KSF files (samples) - normally to be used as drums (but note that these contain no key assignments so they will not show up as a drum-kit). This list is used to load them all in one batch into the synt. When saving an instruments or a collection to a KSC file, then melodic instruments are written as KMP files, and drum kit's as KSF files - all listed in the KSC file.
KMP and KSF files are stored in a sub-directory with the same name as the .KSC file.
Note that each synth can load KSC files made for its predecessor(s), but there are some minor differences between the files made for the respective synths.
The Kronos use a v2 of the KSC format, which probably wont work with the older synths. It includes a "uuid" - a unique number identifying the collection of files. When imported into Awave, this is set as the collection comment text. If you write it back to a .KSC (or .PCG) then the uuid is set from the collection comment if available, otherwise a new uuid is generated.
Also see Korg Kronos PCG, M3 PCG, M50 PCG, Triton PCG, Triton LE PCG, Trinity PCG, KMP and KSF files.