The icons are LGPL. Here is everaldo's statement on the matter: http://lists.kde.org/?l=kde-artists&m=111947174930644&w=2

However, the KDE artists group apparently made a decision in the past that they only want to use icons in vector format. To an artist, the vector format is the "source code" that allows them to modify the icon, and they don't want to use icons in KDE unless they can redistribute these vector files for people to modify in the future.

If you read through the entire thread, you'll see that there was a lot of controversy over that decision even within the KDE artist community. Some people felt that PNG files were an acceptable choice. Others felt that PNG wasn't the "preferred format" for editing an icon, which conflicted with the LGPL requirements. Ultimately, they decided to stick with vector format icons.

I'm a non-artist, looking for icons to make my open source program look nicer. I wouldn't know how to work with vectors anyway, so for me, PNG is the preferred format for editing the icons. That being true, there should be no legal reason why the PNG files can't be modified and redistributed via LGPL. The KDE artists have a different "preferred format" for editing the file, but that't their preference, not mine.

So the bottom line is that everaldo is giving these icons away as LGPL. People are free to modify and redistribute them in PNG format under the LGPL license.

Thank you, everaldo, for all the work you've done. As an open source developer, I've also gotten critisized a few times by third parties who want me to use a different license. But don't let that get to you. The work you've done is not only beneficial to KDE, but is also a huge factor in helping encourage the broader adoption of Linux and open source technologies. We couldn't get there without you! Thank you from the bottom of my heart.