On the Library page you have 'Featured Content'. This is content that you can flag to draw specific attention to it.
To add a file to the Featured Content section, you click on the 'Star' icon to the right hand side of the file list.
If the star is solid in color, it signifies the file has been added to the Featured Content.
To remove a file from the Featured Content, just click the icon again, and it will return to being a regular file.