Output JSON Feed by default

[DIYgod]

What feature is it?

Output JSON Feed by default

What problem does this feature solve?

Increase readability and efficiency

Additional description

I have found that more and more readers already support JSON Feed, which is a more efficient and easier to read and use format.

So I thought we could start thinking about changing the default output to JSON feeds to drive technological progress.

But I also know that this is a very big change, so more discussion and thought are needed, and I'm just offering my immature thoughts for now.

A more feasible start is to support the optional JSON Feed for now.

This is not a duplicated feature request or new RSS proposal

• [X] I have searched existing issues to ensure this feature has not already been requested and this is not a new RSS proposal.