When working with a Windows 10 ISO, "index" typically refers to the Index Number of specific operating system editions (like Home, Pro, or Education) contained within the image file. Windows ISOs often use a single install.wim or install.esd file to store multiple editions, and each edition is assigned a unique index number for identification during installation or servicing. How to Find the Index Numbers in Your ISO
If you are an IT professional who needs a legitimate older build for testing, and you fully understand the risks, there is a safer way to use the "index of" method—but not on the public web. Instead, use it within trusted repositories. index of windows 10 iso
Do not download Windows 10 ISOs from random “Index of” pages. The risk is not worth the convenience. Use Microsoft’s official Media Creation Tool or direct ISO download method – it’s free, safe, and always up-to-date with the latest security patches. When working with a Windows 10 ISO, "index"
dism /Get-WimInfo /WimFile:D:\sources\install.esd