Even in the hot phase up to KDE 4.3.0, there have been quite a bunch of fixes to KDE's 4.3 branch. The KDE Release Team has decided to err on the safe side and do another release candidate before KDE 4.3.0 comes out. Dirk Müller has rolled tarballs of the current state of KDE 4.3 and put them up for testers, packages for some distributions are already under way. This also means that the release of KDE 4.3.0 has been postponed for one week. The new planned release date is August, 4th 2009.
One notable change since RC2 is a performance fix for Plasma's caching of rendered SVG graphics that lead to the applet being frozen for a short while after resizing it. A regression that cropped up after RC2, and which resulted in HTTP redirects being broken has been fixed in RC3 as well.
Please give this KDE 4.3 RC3 some good testing to make sure KDE 4.3.0 will be as flawless as possible.