The Keyboard Layouts subkey stores data that associates the keyboard layout for each locale with the dynamic-link library (DLL) for the keyboard layout or Input Method Editor (IME) that supports the language of the locale.
The names of the subkeys of Keyboard Layouts correspond to Windows 2000 keyboard layout codes, which are eight hexadecimal digits. The first four digits of the codes indicate whether the keyboard layout or IME is the default layout for the language (indicated by 0x0000) or a variation of the default (all other values). The last four digits are the standard locale ID.
For example, the 00010402 subkey represents the first variation of the keyboard layouts associated with locale 0402 (Bulgarian).