CONFIG_USB_F_UAC1_LEGACY (not configurable)

modulename: usb_f_uac1_legacy.ko

configname: CONFIG_USB_F_UAC1_LEGACY

Linux Kernel Configuration
└─>Device Drivers
└─>USB support
└─>USB Gadget Support
└─>USB_F_UAC1_LEGACY
In linux kernel since version 4.2 (release Date: 2015-08-30)  
source code:
drivers/usb/gadget/function//

is depended by
CONFIG_USB_AUDIO