How to avoid exposing my MAC address when using IPv6?

Problem

On my Macs, each IPv6 address includes the MAC address of a specific computer (not of my router). Sites such as ipv6-test.com not only show it, but even tell me it belongs to an Apple computer. This feels like a super cookie, and might apply to other operating systems as well. How can I avoid my MAC addresses from being exposed? Background: the MAC address is not in plain sight. Like for : Take the last 64 bits (the host identifier) and add leading zeroes: . Strip the part from the middle. If these bytes are not there, then there's no MAC address. For the first byte: complement the second low-order bit (the universal/local bit; if the bit is a 1, make it 0, and if it is a 0, make it 1). So: (00000000) becomes (00000010). Presto: translates back to MAC address . Note: since macOS 10.12 Sierra, according to Ars Technica Apple has adopted a new way of generating stable addresses that are not based on a MAC address, which Windows apparently had already been doing for years. This question …