I am German. The letter is called "Eszett" or "sharp S". Its pretty easy, you have words with single s and double s. And the s / ss tell you how much emphasis you put on the s.
A ß is meant to go beyond this and use sss, which looked stupid, so the Germans have invented the ß to represented and s that takes even more emphasis.
Expamples of these would be: Hase Hass Spaß
But in recent reforms the ß has been in decline and been replaced with a regular ss. In Switzerland this letter does not exist, they always use a ss, which in turn makes some words with different meaning and the same spelling. For example in Switzerland the sentence "Schokolade sollte in Massen genossen werden" mean both "chocolate should be consumed in masses" as well as "chocolate should be consumed with care". I find this funny. :D
I think it might be used the same way in Pyqsi as well. I personally consider ß to be more of a letter for writing and pronunciation then for spoken language.