Example with json in readme, how to get this to work

[Japhys]

Is this plugin being maintained? Not much activity.

I am probably doing something wrong (not a coder) but where do I put the json content? I just tried this from the readme file. The non json example does work

[google-maps width='100%' zoom=2 scrollwheel=true panControl=true content=json]
[
{"key":"20:53", "lat": 22.42559832, "lng": 114.2123749 },
{"key":"21:09", "lat": 22.41401143, "lng": 114.21253759 },
{"key":"21:20", "lat": 22.42327849, "lng": 114.21259051 },
{"key":"21:42", "lat": 22.44140609, "lng": 114.17303335 }
]
[/google-maps]

Map is empty. Am I missing something?
Anyone using this with json?