Question about UI

[snakemeat]

I can't seem to figure out what the 'P' represents in the game list UI.

For example, using the Angler King set from MAME 0.260, the game name is in white, but the 'P' on the far right of the same line is "grayed out."

[RingoStarr39]

The "P" stands for "playlist," meaning that there is a list of the track names available for that game.
The track names are either taken from official sources or when one doesn't exist, someone (usually myself or ctr) will do research to figure out where/when each track plays in game.
Otherwise the track names are either pulled partially from game data or left blank.