- It seems that all handling of JSON pages with content model Tabular.JsonConfig (.tab pages) on Wikimedia wikis is currently handled by the JsonConfig extension, so that would probably be the best place to implement such an editing interface.
- This data structure is quite tightly defined, so an editing interface like a form for each field within a dialog is feasible.
- The data array is tricky to edit even for someone who is familiar with JSON, so as a first step, adding a table editor would be helpful.
This task is scoped to editing .tab pages, but here are notes on editing JSON more generally, perhaps for making into another task:
- example on English Wikipedia