audk/DuetPkg/BootSector/bin
..
Gpt.com
Mbr.com
Readme.txt
St16_64.com
St32_64.com
Start.com
Start16.com
Start32.com
Start64.com
bootsect.com
bs16.com
bs32.com
efi32.com
efi32.com2
efi64.com
efi64.com2

Readme.txt

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

These binaries are used to make the bootable floppy or usb disk. 
The binaries of boot sector are built from DuetPkg\Bootsector\BootSector.inf at r8617 with following steps:
1) enter edk2 workspace directory from command line windows.
2) run "edksetup.bat"
3) run "build -p DuetPkg/DuetPkg.dsc -a IA32 -m DuetPkg/BootSector/BootSector.inf"