CODECOMPOSER: A key icon above "include" folder

Hi expert,

    When my customer used CCS, they found in the program directory of the Project Browser Window, a "key" icon was displayed on the "include" folder. I have attached the picture below.

    Now my customer wants to know:

    1. What does this icon mean?
    2. When will this icon appear?

    Could you please help me about that? Thanks a lot!

BR

Julia