What is the purpose of the blue area in Final Cut Pro timeline for still images?

THE part of the timeline in the attached screenshot—where I've written "this area"—is part of the representation of a still image in the timeline. That blue area takes up a lot of space, almost one third again of the space taken up by the image. When I'm working with lots of layers it takes up TOO MUCH space. I've searched online for answers as to what the function of that blue chunk is, but chat and deepseek just make things up. Does anybody know what function that blue area performs? It SEEEMS useless, and the only way to make it smaller appears to be to change the timeline view and shrink the IMAGE portion, the "good" portion of the clip. If there is any way to get rid of that blue area without sacrificing the image (or the audio waveforms), I'D LOVE TO KNOW ABOUT IT???? If there isn't any way, I'd still love to know what purpose it serves. It never seems to hold any data. THANKS.

[Re-Titled by Moderator]