This sounds similar to what I am doing with my projects, except I'm doing it manually. I put the required pages into files and import them to the wiki. Examples:

• https://github.com/Nikerabbit/mediawiki-extensions-Sanat/blob/master/SanatImport.php import script (there is also export script, though I rarely use it)
• https://github.com/Nikerabbit/mediawiki-extensions-Kotus/tree/master/slangipaikannimet/maintenancepages wiki content

It would be nice indeed if I didn't need to run that script every time.

We'll be talking about possible approaches to this in a MediaWiki-Stakeholders-Group meeting this Friday: E582. We'd love to get your input.

An idea, discussed at SMWCon Fall 2017, is to have a mechanism to directly serve the content of static sources (i.e. files) bundled with an extension.

Just so this doesn't get unnoticed, SMW does import static content [0] (since 2.5) during the install.

[0] https://github.com/SemanticMediaWiki/SemanticMediaWiki/tree/master/src/Importer

We have a slightly different but related issue. We are looking for a mechanism to synchronize templates and forms between wiki's in a wikifarm. So newer version of template A from wiki 1 to wiki 2, newer version of template B from wiki 2 to wiki 1 and so on. Using Git as a central repository. The solution Lex showed at SMWConv Fall in Rotterdam comes close to the need we have (development of forms and templates takes place in different wikis of the farm).

@Waanders: at https://smw-cindykate.com/main/Component_759410#What_can_be_used_how_in_a_facets-management-script.rb.3F you can see my current implementation of the envisaged https://www.mediawiki.org/wiki/StructuredDataManagementSuite which I will use tomorrow for the first time in a customer context.

Somewhat different usecase, but MediaWiki-Vagrant imports documentation from puppet templates. See mediawiki::import::text.

I'm planning to write something more integrated for git-hosted gadgets (T71445: Implement a proper code-review process for MediaWiki JS/CSS pages on Wikimedia sites) which would probably have some interface for admins to links wiki pages to git files, and then it would update the page automatically when the file changes in git.