I have a question about document structure, because I want to  
structure a series of products correctly and I do not know if I  
understand everything in the manual about it well enough.

Must I understand that "\startlocalenvironment[abc]" within an  
environment file means that this codeblock is used only for  
typesetting product/component abc and excluded automatically when  
another product/component is typeset?
Or is it just a declaration analogous to "\startenvironment file  
setups \stopenvironment"?
But then I don't understand why the manual does not tells me
"\startlocalenvironment[abc] file setups \stoplocalenvironment" as it  
does for \startenvironment

The macro "\localenvironment name" gives me some headaches. I might  
guess usage in a master setup file as:
\localenvironment abc % load environment file abc.tex if typesetting  
product/component abc
\localenvironment xyz % load environment file xyz.tex if typesetting  
product/component xyz
How does this relate to the above question about setup-file structure?

Hans van der Meer