The 12" Macbook was sold from 2015-2019: https://en.wikipedia.org/wiki/MacBook_(2015%E2%80%932019)

To resolve as Yes it doesn't need to be called Macbook, or have a 12 inch screen. It should be a laptop running Mac OS that is physically smaller than the current Macbook Air and weigh at most 1 kg. It should be available for sale on or before 31 December 2023.

It is rumored be released around the end of this year: https://www.macrumors.com/guide/12-inch-macbook/