What is this drive called RUFUS BOOT after creating ISO installation with Rufus?

After creating the Windows 11 26H2 ISO using Rufus, I noticed this drive called RUFUS BOOT.
What is this?

The other drive called CCCOMA_X64FRE_EN-US_DV9 (E:) is normal, that's the one with the main Windows 11 ISO files inside of it.

But this RUFUS BOOT is concerning because it also shows a red line that the drive capacity is getting low.

Rufus supports booting from NTFS in native UEFI mode through its UEFI:NTFS feature. When Rufus uses NTFS, it creates a small FAT partition labeled RUFUS_BOOT (previously UEFI_NTFS) containing the UEFI:NTFS bootloader. The firmware boots from this small FAT partition; UEFI:NTFS then loads an NTFS driver and launches the Windows UEFI bootloader from the main NTFS partition. This allows Rufus to use NTFS for Windows installation media when the ISO contains an install.esd or install.wim larger than FAT32's 4 GB maximum file size.

The UEFI bootloader and NTFS driver used by current versions of Rufus are Secure Boot signed, so Secure Boot normally does not need to be disabled to use UEFI.



The screenshots below show USB installation media created using Rufus.
The first screenshot shows the Rufus UEFI:NTFS bootloader.





The Media Creation Tool works differently: when it creates a FAT32 USB flash drive, it can split a large Windows image into install.swm, install2.swm, and so on. This keeps each split image file below FAT32's 4 GB maximum file size.

The screenshot below shows USB installation media created using the Media Creation Tool.

Did you wrote that .ISO to an USB-stick? The USB contains 2 partitions. A small one with a FAT32 boot partition to boot from and to call the larger partition to install Windows. Normally you should see only one: Partition 2. Partition 1 is normally hidden. When you reboot your system and enter the bootmenu of the motherboard (With an ASUS motherboard that is F8, with other brands an other key) you will notice 2 partitions with the same name and size. The top one is always the boot partition. The second one below it is the Windows (NTFS) partition. Windows can not boot from a NTFS partition only from an FAT32 partition. If you want to install Windows select the bottom one (partition 2) and Windows will start to install.

In case of Rufus v4.15 this is now normal behavior. I have also wrote an .ISO with Rufus to an USB-stick (Zorin-OS) and this is wat I see also when I attach the USB stick into my system: (If you don't want to see that boot-partition: Use diskpart to make that partition hidden)



So this is normal behavior.....