What is this yellow stripe?
 

I've searched this site and the web, but maybe "stripe" isn't the right term.

From time to time I see this vertical yellow stripe on T205's where there's no other yellow on the card, but I've never seen it on the same card twice. It's always in the gold part of the border, so maybe it's part of the ink that makes up the gold, but I have no idea.

If this has been discussed before, please provide a link or let me know what it is.

Thanks,

I think it actually looks cool with blue.