According to Toms' Hardware, the CPU can process 12 threads simultaneously and CPU expert @InstLatX64 believes that this is AMD's Phoenix 2 processor, with two high-performance Zen 4 cores and four energy-efficient Zen 4c cores.
AMD Eng Sample processor marked 100-000000931-21_N [Family 25 Model 120 Stepping 0] features 12 logical cores (i.e., six physical cores with simultaneous multithreading) and reports about 1MB of cache, which indicates that the MilkyWay@Home client cannot work out the cache featured by the chip.
The listing does not prove that this is AMD's hybrid Phoenix 2 processor with Big.Little-like core configuration, but it does match the rumours.
Phoenix 2, which is nothing like the Phoenix APU is rumoured to feature two 'big' Zen 4 cores with 2MB L2 and 4MB L3 cache and four 'small' Zen 4c cores equipped with 4MB L2 and 4MB L3 cache.
The APU has an RDNA 3-based integrated GPU with 512 stream processors and has a DDR5/LPDDR5X-supporting memory subsystem.
@InstLatX64 claims that AMD's Phoenix 2 APU has an A70F8x CPUID, whereas CoelacanthDream asserts that the CPUID of the processor is 0x00a70f80.