How do I look up differences between these 2 tickers?

The tickers in question:

VOLCAR-B.ST – went public y/2000≈
VOLV-B.ST – went public y/2021≈

Why does Volvo have 2 separate tickers? How can I find more info regarding the tickers?

The answer is probably very simple but I can't figure it out. Any help is greatly appreciated.