Babe Ruth hit 60 home runs in what was a 154 game season, Maris was in a 162 game season. The * was to note there was a difference in the length of season.
Yes, yes, I know that. But that's about 1/10 of the story. There was a pretty good book written about "The Asterisk". IIRC, that was even the book's title. The 154 versus 162 games was the excuse they gave, but a lot more was going on than that. Enough to fill a book, in fact.
In the end, they gave up on the whole idea of asterisks in the record books for 154 versus 162 game seasons. They never had asterisks in the NFL even though the length of the season has slowly but surely expanded since the 1960s.
Like the anti-FT8 "jihad" the whole asterisks thing
was a failure and you won't see it again.