Right, so this Development Platform, Applications and Plasma Workspaces trinity nonsense extends all the way down to them having separate release notes. Oh joy. There's nothing I look forward to more than digging through not one, not two, but three sets of release notes while having the flu, and while having done nothing but work for the past seven days (working from home means you don't get bedsies when you're sick). This sounds like a rant, and it is - for the love of Fiona, KDE, quit with this nonsense already. Just go back to calling yourself KDE. Nobody cares. Everybody still calls you KDE. Deal with it.
Rant over, let's get started with the good stuff.
They've revamped the Activities paradigm which went quite underused, and made it easier to discover and use. "By right clicking to the window title, you can now make applications and files part of an activity. Changing to this activity, the Plasma workspace will show you what you need when you need it. The process for adding, renaming and removing Activities has also been improved," the release notes for Plasma Workspaces state.
Other improvements in Plasma Workspaces include a revamp of Power management, and, joy to the world, more performance improvements for Kwin, something which has been sorely needed since day one in KDE4.
Moving on to KDE Applications, there's lots of random improvements here and there, and little really stands out to me. When it comes to development platform, there's QML, which is kind of a big thing. "With the new release, the Plasma framework gains support for Plasma widgets written in QML, Qt Quick's declarative UI language," the release notes write, "While existing widgets continue to function just as before, QML is now the preferred way to create new widgets."
"By modularizing the KDE libraries further, parts of the KDE platform can now be built for mobile and embedded target systems," they state, "Reduced cross-library dependencies and allowing certain features to be disabled, allow KDE frameworks to now be easily deployed on mobile devices. The mobile profile is already used for mobile and tablet versions of KDE applications, such as Kontact Touch, KDE's mobile office suite and the tablet and handset Plasma user interfaces."
Of course, KDE 4.6.0 will find its way to your distribution of choice.