Acumatica Rest API. [How to retrieve acumatica rest api odata metadata in json format]

Question

Acumatica support OData and below is the docs link https://help-2018r1.acumatica.com/(W(4))/Wiki/ShowWiki.aspx?pageid=339f2b58-c593-456a-8bad-a8eb7b7db8d8

I tried cou