It would be interesting to think about how this fits into a plan to advance MediaWiki and other large FOSS projects guided by the Foundation into higher levels of the w:OpenSource Maturity Model. Today I don't know that MediaWiki even qualifies for the "basic level" of that model.
Talk:Documentation/Maturity model for MediaWiki technical documentation
Fitting into a larger FOSS software maturity model
Yes. Thanks for bringing this up. I have been reading about that and thinking about it a bit. There are a number of Open Source Maturity Models -- https://en.wikipedia.org/wiki/Open-source_software_assessment_methodologies, which we can and should draw from to inform a maturity model and strategy for Mediawiki/Wikimedia technical documentation.
In the end, I think the exercise of creating any sort of maturity model or strategy is really about deciding what approaches to technical documentation and communication resonate with and serve our community's needs and striving to get to that place.
Looking for something about a process for managing staleness
I think at a collection level or an organization level, I expect mature technical documentation to have an effective process for managing the staleness of documentation. E.g. having API documentation exist next to code can make code review a process for checking the staleness of documentation. For documentation on a wiki page, I'd like some way to flag and discover documentation that might be out of date.