Anybody know what kind of glider is in this pic?

One clue would be that little red "DG" sticker :-)

I 'm pretty sure it's an LS10

IS-28-B2 for sure!!

Funny that nobody so far had the idea to just look at the home page of
the WGC Szeged. :-)

And the winner is... (Hint: incidentally or not, the contest sign
happens to have a meaning.)