The log information of this commit pointed out that the reason for introducing MTC is to ensure that OpenBSD can work in other places outside the earth. According to reports, Coordinated Mars Time (MTC) is a time zone plan for Mars, similar to Universal Time (UTC) on Earth. MTC is based on the average solar time calendar defined by the prime meridian of Mars.
The name “Coordinated Mars Time” is modified from the Earth’s “Coordinated Universal Time”, but this name is misleading: there is a concept of using leap seconds in Coordinated Universal Time, but there is no leap second in Coordinated Mars at all.
The rotation speed of Mars is slightly slower than that of Earth, and the time of a day is 24 hours, 39 minutes, and 35.244 seconds. Therefore, OpenBSD’s programs and interfaces for processing time will have problems outside the earth. By introducing support for coordinated time on Mars, you only need to set the time zone to TZ=MCT when running OpenBSD to work normally on Mars.