All functions in the API-MS-Win-Core-Util-L1-1-0 set are documented exports from KERNEL32, mostly from as far back as version 3.51:

The implementation of Beep in KERNEL32 version 6.1 and higher is a stub that transfers the handling to wherever the schema redirects this API Set, except for some pre-processing.

The other functions are each forwarded to a corresponding NTDLL function.

New Locations

For each function that KERNEL32 version 6.1 transfers to the API Set, a non-trivial implementation is exported from KERNELBASE version 6.1 and higher.

All the functions that KERNEL32 forwards to an NTDLL function are also exported from KERNELBASE version 6.1 and higher, also as forwards to the NTDLL function.

Schema Redirection

The Windows 7 schema redirects this API Set to KERNEL32, except that when KERNEL32 itself imports from the API Set, the redirection is to KERNELBASE. Thus: