As a Wikimedia technical contributor
I want to use Page Demo and Catalyst to test and demo complex system changes in a pre-merge environment
So I can maximize my productivity while minimizing post-merge defects and change requests.
The Wikimedia project's content wikis have various types of specialization across the wiki farm. There are several groups of project wikis which largely have the same extensions and core configuration other than the default interface and content language used (think en.wikipedia.org, de.wikipedia.org, fr.wikipedia.org, es.wikipedia.org, ...). There are also a number of specialized wikis that provide some unique service for the wiki farm such as commons.wikimedia.org (media hosting), www.wikidata.org (wikibase hosting), login.wikimedia.org (authentication service), and others. When constructing a demo/test environment for complex feature it would be nice to be able to create a more diverse wiki farm where for example one could have a few Wikipedia like content wikis, a Commons like media wiki, a Wikidata like wiki, a loginwiki like auth wiki, and apply patch(es) that change features where a Wikibase client is used to interact with Wikibase data exposed by the local commons and wikidata wikis from both LTR and RTL content language local wikipedias with CentralAuth shared auth and login wiki same sign-on functionality. In an environment like this there would still be a reasonably large number of extensions and configuration settings that could be shared by all wikis (even if they were not being actively exercised everywhere), but there would also be a need for some specialization of both extensions and config to setup various client/server relationships.
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