Wikibase (and Wikibase extensions) maintain high- and mid-level documentation in the docs folder. To expose this documentation in a canonical location on the web, it would be useful to automatically copy the latest version of these files to mediawiki.org, when a change is merged.
The following scheme could be used:
Files from an extension's docs folder get copied to mediawiki.org as subpages of the extension's homepage. For instance, docs/options.wiki in the Wikibase repo would be copied to Extension:Wikibase/docs/master/options.wiki. To make documentation of (snapshot) releases easily accessible, the documentation should be copied (for now, manually) when a new release is made. The path for a release could looks something like Extension:Wikibase/docs/REL1_28/options.wiki.
Documentation in plain text (and in markdown?) should be wrapped in <pre> tags when copying.