Those specs have probably been written assuming max. 2 memory slots, max. 8GB in each, rather than stating some kind of absolute engineering limit in the CPU it

Those specs have probably been written assuming max. 2 memory slots, max. 8GB in each, rather than stating some kind of absolute engineering limit in the CPU itself. 16GB SO-DIMMs are very recent and only available from a single vendor, but I have seen reports of them working at least on Broadwell CPUs with just a single memory slot.