Barry Warsaw writes:

Currently, JSON is the only supported output format. I'd be open to patches that provide other output formats.

Please, no. "Filters are one honking great idea. Let's do more of those!"

I think most of the interesting programming languages people might write Mailman functionality in have JSON parser/generator modules. JSON is not a bad serialization format (I think it's pretty good, actually, but conservatively it's not bad, right?) Let's stick to that rather that proliferate incompatible interfaces.