Thread:Support/About MediaWiki:Apihelp-sitematrix-description/sv/reply (2)

I think your description is a lot clearer than the current message:
 * "The code is either the unique identifier for specials or, for languages, the project code."

Alternatively a combo such as:
 * "The code is either the language code + project code for content projects or the subdomain + main domain for all the others.