This is currently used with the biblio.format.record_entry.email and biblio.format.record_entry.print templates, for the open-ils.search.biblio.record.email and open-ils.search.biblio.record.print OpenSRF methods, which.. I don't think are actually used for anything yet. :-D But the idea behind those methods is that you can specify a set of bibs and provide templated output to print or email. It shoves these bibs into temporary buckets (at the time I didn't realize you could send user data when firing events), and with the cleanup handler, deletes the buckets afterward. If the cleanup handler were to actually look test for btype="temp" before deletion, we could re-use those templates with real buckets, and similarly, we could give the Bookbag CSV template that cleanup method and use it for selected bibs not actually in bookbags (say, on the search results page).
