hey - I'm trusting - trust me I 'm trusting. What else can a noob to PCLOS do 
OK - I did this:
1. Opened Synaptic, ran Reload and then searched for kdesdk4.
2. Found it and clicked on "Mark for Installation". This listed over 100 files but nothing like Kate could I see. So I backed out.
I don't really want to install all these other files in the hope that Kate is buried in there somewhere.....
I gotta be missing something here. Philosophical question. How do you know if you are missing something when you don't know what it is?
SDK stands for
Software
Development
Kit, so the extra files are there to aid in that endeavor. Mostly they are the devel packages for the individual applications, but other useful tools are in the package also. I particularly like
Kompare, who's defined purpose is checking and generating diff patch files. I find it useful for comparing any two text files that represent different versions/rewrites of the same subject. I'm not a developer, but for more than 10 years I've always installed the various SDK packages, just to play around with the tools and see if I can find uses for them that are practical for me. For me, Kate and Kompare together justify installing the sdk package, even if I never use any of the rest of it.
You find out what you are missing by installing those things who's use you don't know, then playing with them. Unlike Windows, the applications are free, so it costs you nothing but time to explore them. That's part of the fun of using Linux; there's so much to discover. What you find use for, you keep and enjoy. What you have no use for, you uninstall to make room for more exploration.
