Equal hours, different anchor.
Byzantine Time uses ordinary equal-length hours. Its difference is the beginning of the cycle: sunset rather than civil midnight.
Sunset moves, so the clock moves.
Because sunset changes with place and season, the civil-clock moment at which Byzantine Time returns to 12:00 also changes.
Why include it in SOLAR?
It offers a complete time system rooted in a natural event. The same sky, day and reminder events remain visible while the main number adopts a sunset-based reading.
Not the same as Seasonal Hours.
Seasonal Hours change their duration because they divide daylight and night into twelve parts. Byzantine Time keeps equal hours and changes only the local sunset anchor.
Unavailable states
If a date has no usable sunset, SOLAR does not invent a new anchor. The mode reports that the value is unavailable for that state.