You uncultured bigot, It’s obviously the winners of the Euros vs the winners of the Copa America. *I had no clue either, just copied from Wiki*
Only thrice according to Wiki. First two were in late 80s and early 90s, now looking like it’s been revived and gonna be a thing, next one is in 2025.
I assume it means Grand Final - issima is generally an over exaggeration of something....such as cup winners cup