It would be useful to be able to check the header information on an XML database dump file to confirm the database of origin. I'm imagining something like the dbname that you can get from the API (e.g. http://en.wikipedia.org/w/api.php?action=sitematrix).
My current use-case is error checking. I want to make sure that the XML dump file being processed by originated from the intended wiki. Right now, I need to parse filenames in order to do that and that makes me sad.
I propose adding a field to <siteinfo /> called <dbname /> that would contain this value.