New feature request, I think this can't be done by changing a config variable.

What Json pages in particular pose security issues?

What is the security issue here?

In T155900#2958255, @Krenair wrote:

What Json pages in particular pose security issues?

These pages may contain user settings which used by scripts.

Scripts should not be putting any security-sensitive settings on openly-editable pages. That's a problem with the scripts, not MediaWiki's handling of json pages.

In T155900#2958399, @Iniquity wrote:

In T155900#2958255, @Krenair wrote:

What Json pages in particular pose security issues?

These pages may contain user settings which used by scripts.

Can you provide some examples please?

In T155900#2958412, @Krenair wrote:

Scripts should not be putting any security-sensitive settings on openly-editable pages. That's a problem with the scripts, not MediaWiki's handling of json pages.

I know, but why JSON pages openly-editable? What difference between JSON page content and JS page content in user namespace?

In T155900#2958420, @Legoktm wrote:

Can you provide some examples please?

For example, this gadget has this localization page. If I want to save this gadget in 'User' namespace, and localize it in other way than one day somebody can come in and break the translation. Put the virus links, pictures smth else.

OK, this is not a security bug then. I'll mark it as a duplicate of T76554: Restrict editing of .json pages in the user namespace (like .js and .css).