Hi. Don't think it's a feature.
- Open some JSON page.
- Watch the green table structure.
- Click on Edit source.
- Change something.
- Click on preview.
- Expected: changed green table structure.
- Got: a copy of wikicode to be saved (possibly with a proper indentation).
Does not happen on all JSON pages, some of them are broken and some are not, don't know which. So, try, for example this one.
View mode:
Edit mode:
May or may not have something to do with the recently deployed T146771. Thank you.

