It’s easy to guess what happened: they developed an IPv4-only network stack and baked the limitations and constraints of IPv4 into it: private addresses are mandatory, public addresses are scarce, and NAT is required.

Then they got told to “do the needful” and make IPv6 happen, so they did… by weaving IPv6 support through the tangled briar patch of their codebase. They wove it through the NAT, the tiny public address blocks, and the mandatory private address spaces on virtual networks.

The result is IPv4 with a sticker on it with a hand-written label that says “IPv6”.

“Job done boss!”