What are these EUR tickers of foreign companies: PJXC (Petrobras), 2RR (Alibaba), APC (Apple)

Hello,

I have noticed many tickers denominated in EUR of many foreign companires, usually listed in FRA or ETR exhanges.

Does anyone here invest into these and why?

I wonder if it is worth converting source stock tickers that I hold on IBKR to these. What would be the advantages and disadvantages of such conversion?

And most importantly: Will Germany charge me extra dividend witholding tax compared to holding the source stock ticker directly?