Summary: A list of applications which at some point have registered with the sound menu
Each media player which abides by the MPRIS2 spec will automatically appear in the menu. This array should contain the desktop file names (minus .desktop suffix) of applications which have at some point appeared in the menU. This allows the menu remember and display offlined applications.
In the array, there must be one and only one while space behind the comma(,).
Or else, the default value can't be restored