The WOW key at HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\WOW stores configuration data for the Win16 on Win32 subsystem; aka Windows on Windows.

The WOW key contains subkeys that have the same names as headings in the System.ini file. The value entries in these subkeys are the same as the values in the 16-bit Windows 3.x System.ini file.