https://www.gamespot.com/articles/sega-mega-drive-genesis-mini-revealed-will-include/1100-6458287/

Similar to Nintendo's NES Classic and SNES Classic, Sega revealed that a Mega Drive Mini will be coming to Japan to celebrate the 30th anniversary of the original console. The news came from the Sega Fes 2018 event which featured a number of announcements and celebrated the company's history. Although details are sparse, we know that it will have pre-loaded games on the machine, a form factor of about a quarter of the original size, and a release date sometime this year. There is currently no word on a North American or European version.

The Mega Drive, known as the Genesis in North America, came out in Japan in 1988 and featured a number of great games like Sonic the Hedgehog, Phantasy Star IV, and Streets of Rage II, just to name a few. The official AtGames Twitter account said that it is tasked with creating the Mega Drive Mini, although the tweet was subsequently deleted. AtGames is a licensed manufacturer of retro Sega hardware, but its previous Sega Genesis Flashback console was received poorly.