Free Space Confusion

This may be relatively simple to answer, but I didn't want to ask it in the chat incase it wasn't. I know there's a thread here that lists the Free Space in the game, but one thing I see mentioned alot is the F bank. Especially for when moving a song or event. Is the F Bank listed on the free space list? If so, what is it? Still kinda new to the free space thing. Haven't used it much yet but I'm going to need to soon xD.