Hungary introduced new 10000 HUF notes that contain a symbol I couldn't relate to Hungary's history. There were no official notes known to me why they use Patonce Cross on Hungarian notes.
And here is the symbol in question:
I found a few appearances of the same symbol in heraldry. These are from English coat of arms and Canada. I see no relation to Hungary, but I would assume if a symbol is used in the very middle of the note it should have some important meaning.
No, I can find no evidence of any such historical meaning.
While some of the decorative motifs on this and other forin denominations have clear meanings, many do not.
As mentioned in the comments, the central motifs are printed with optically variable ink as an anti-counterfeit measure. The ones with recognizable meanings are directly connected to the portrait on that particular note. On the 1000 HUF note, there is a raven (corvus) which refers to Matthias Corvinus. On the 5000 HUF note there is depiction of the Chain Bridge which was constructed thanks to István Széchenyi.
But like the purely decorative central motif on the front 2000 HUF note, or the one in the upper left corner of this 10000 HUF note, the cross patoncé does not appear to be chosen for any specific meaning. I suspect it was chosen as a visual reference to the cross in Stephen I's crown, much as the central motif on the 2000 HUF (very vaguely and abstractly) echos the shape of Gábor Bethlen's portrait.
