"Last Watched" Site Feature Question

[Mandalorian]

First off, if this thread is in the wrong place, I apologize. I didn't know where to put it...

Okay, so as you all know, under the section for "My Movies"/"Edit Selected" there's a feature for you to mark your movies as "Watched" and update the day you watched it last. First you can change the year, then the month, then the day of the month. After the day of the month, there's another number that goes from 00-23. My question is: what the heck is that number that goes from 00-23 for? It says "Day" at the top, but it obviously isn't the day of the month, or year, if it only goes up to 23. It's bugging me that I can't figure it out. Anyone know?

Thanks