Hello, what is the default font in KDE 4.13+ ?

After upgrading my Kubuntu to 14.04 the font changed to "Abyssinica SIL/9pt" in System Settings and this is one that I do not have on my system, so it defaults to something that looks like Arial.

To my knowledge the default font hasn't changed, although it could possibly have been specified as Oxygen (although this font is still under development). If an Oxygen font package is available, try installing that to see if it has any effect.