When you save a project, it saves unused material

[SoCu]

Hi, I have a project with two slides. I tried adding a transition, and then added another one at the end.

But when I save the project or export it, I see that the file is much larger, and I noticed it creates a folder with the video files containing the transition I tested.

Maybe I’m doing something wrong, but this also happens in version 11.

When the project is saved, shouldn’t it only save the footage actually used in the project?

Thanks.