The way it works is by adding a small (256KB) FAT partition at the end of the drive, which contains an EFI boot executable that loads a Free Software (GPLv3) NTFS EFI driver. Once the relevant driver is loaded, that executable locates the regular EFI bootloader,
on the NTFS partition, and hands the boot over to it.
The one drawback this method has is that, since the EFI boot executable on the FAT partition is not signed by Microsoft (which I don't think it can be, on account of the the Microsoft Secure Boot signing process explicitly the use of GPLv3 as a license), it
is not compatible with Secure Boot.
[...]
[Disclaimer: I am the author of Rufus and UEFI:NTFS]