The "corpus output" (a composite file consisting of a collection of individual contributions -- an issue, or an ad-hoc anthology) now has a complete <teiHeader> element, created by cherry-picking and combining various bits and pieces from the component documents. This is rather a complicated business, and is not always precisely what you want -- for instance, if you combine documents from two vol/issue sets, you'll get idno elements for each volume and issue, but no clear indication of which volume number goes with which issue number. Still thinking about that.