Some related discussion:

From 3 months ago: "A relativistic framework to establish coordinate time on the Moon and beyond" <https://news.ycombinator.com/item?id=40934608> (73 comments).

From 6 months ago: "White House wants Moon to have its own time zone, Coordinated Lunar Time (CLT)" <https://news.ycombinator.com/item?id=39916102> (247 comments).

From 2 years ago: "Europe pushing for lunar time zone" <https://news.ycombinator.com/item?id=34982157> (383 comments).

To wit: they want to build a Lunar GPS/GNSS nav system, and this is the time-sync part of the nav system. Lunar time runs faster than Earth TAI atomic time by 1 millisecond every 2 weeks, 21 ms per year, or 1 second every 48 years.