This is the location for extra files that are needed to build the initframfs.
├── defconfig Default Buildroot configuration
└── overlay Files that will be directly put into initramfs root
├── config
│ ├── fstab
│ └── interfaces.d
│ ├── enp0s1 Configuration of the RJ45 interface
│ └── enp0s2 Configuration of the SFP+ interface
├── (debootstrap) Debian installation scripts, created by scripts
└── init Script that does most of the work