Discussion at https://en.wikipedia.org/wiki/Wikipedia:Page_Curation/Suggested_improvements#Remove_userspace_from_Special%3ANewPagesFeed%3F
We can either turn this off by
- only modifying $wgPageTriageNamespaces, or
- also stripping it out of the code entirely.
#2 might be better because it reduces complexity of the software, which is good for maintainability. So for example, we could remove namespace 2 from extension.json, we could delete the MFD code from delete.js, we can get rid of the code hiding the tagging menu from the toolbar, and we can get rid of the code hiding the "message the creator" code from the "mark as reviewed" menu.
A one time SQL delete query might be needed for pagetriage_page and pagetriage_page_tag entries for pages in namespace 2 (user).
I see the primary benefit of this as not encouraging patrollers to use limited patrolling bandwidth to patrol a namespace that doesn't need patrolling. There are also some technical benefits, such as reduction in SQL table sizes and simplification of the code.