Is there a risk that SPLG will switch to tracking a different index other than the S&P 500 again?

SPLG currently tracks the S&P 500 index, but I’ve seen people say that in the past (before 2020), it tracked different indexes: Russell 1000 -> SSGA Large Cap Index -> S&P 500. Apparently the ticker was also changed. (Links to some sources in comments.)

However, when I look at the 10-year return, it seems very close to other S&P 500 ETFs, like VOO, making me think it didn’t actually change what it was tracking…?

Can anyone explain/confirm what actually happened, as well as explain what would happen if the ETF changed what it’s tracking again? Is that even possible? Can they just switch that up on a whim? And if so, would I have to sell my position and buy into a different S&P 500 fund? (That would not be optimal, especially in a taxable account.)

Thanks!