Where are the downloaded files for installing Windows 10 stored?

Question

Windows

When I clicked to update, first Windows itself loaded something and then I clicked on cancel and watched that the C drive was filled up so it repeated 2 times, So where are those files stored?

Answer 1

Hidden folders on the system drive:
$windows.~BT
$windows.~WS

Answer 2

In a specific case, this plugin is used - slicknav.com