From https://bugzilla.redhat.com/show_bug.cgi?id=1092170#c3: Some writers here in Brno have been working on docs written in Mallard (http://projectmallard.org/). These include RHEL7 desktop help and some internal ECS documents. Supporting Mallard in PG would allow us to easily import this content and integrate it with existing docs in PG. Mallard also has great support for multimedia content, and we are currently looking into supporting it in the Customer Portal infrastructure, so being able to work with Mallard in PG would be a great plus for writers who want to deliver rich content in their docs.