There is no mapping to hours and minutes.  Those things are abandoned.  I said "metric".  One day sunrise is 1730251233 the next day it is 1730337648.  You then put that into your own local mapping to local hours/minutes if you can't let go of the past, or just to an sunangle if you can. 

 🤯 

 the number (Unix time?) is hard to parse but that could be improved.

i like global standards that make it easier to understand each other.