This was released on twitter as part of the 45th anniversary of Gundam as a franchise and to mark the 2-year anniversary of the original broadcast date of Witch From Mercury (October 2nd, 2022). Check out the Crunchyroll article for additional information. Synopsis of the first season from AniList:

A.S. (Ad Stella) 122

An era when a multitude of corporations have entered space and built a huge economic system. A lone girl from the remote planet Mercury transfers to the Asticassia School of Technology, run by the Beneritt Group which dominates the mobile suit industry.

Her name is Suletta Mercury. With a scarlet light burning in her pure heart, this girl walks step by step through a new world.