[NTG-context] How to read syntax descriptions

In the beginner's manual, we have for \startitemize the following: \startitemize[..,..,..][..,..=..,..] ... \stopitemize I was wondering how do you read this in english? Based on the examples, am I correct to say the following? 1) The \startitemize is optionally followed by a comma separated list of parameters enclosed in brackets. 2) Then a set of key-value pairs enclosed in brackets follows. Again this is optional. If this is correct, then what about \setupitemize?. It says \setupitemize[.1.][..,.2.,..][..,..=..,..] So again let me guess .1. stands for a number The third set could be key-value pairs What about the set in the middle? Can we have an explanation for these please. Salman