Hi,
If you right click on a icon and select "Properties... Customize Tab", or "Change Icon", You will get a screen to "Browse" and have a location already available...
Most Icons Windows 10 uses are actually located in C:\Windows\System32...
The two primary locations are...
C:\Windows\System32\shell32.dll
C:\Windows\System32\imageres.dll
Plus a few in C:\Windows\System32\imagesp1.dll and C:\Windows\System32\filemgmt.dll...
These locations are "Libraries" that are only accessible when using a "Change Icon" setting of some type... Even if you were able to "Extract" the files, I don't know if they would be usable this way...
I have never actually tried...