Request: Resources for converting EWKB to numeric coordinates?

Hey! This is a really nifty package you've built out! Could you please point me to the resources you used to figure out the logic for transforming EWKB into numeric coordinates? For example, how did you know which bytes represent the SRID vs. the X,Y coordinates? I'm asking so I can implement a similar thing for other geometry types.

Thanks so much for your time!