From REST docs: 

'This endpoint is used to test the Gateway's settings prior to either creating or updating it. The information will be used to attempt to create a link between the API Manager and the Gateway, by simply trying to ping the Gateway's "status" endpoint.'

This part:

'The information will be used to attempt to create a link between the API Manager and the Gateway'

( http://www.apiman.io/latest/api-manager-restdocs.html )

This means the endpoint 'http://localhost:8080/apiman/gateways/' [PUT] 

is used for/to/only Apiman itself ? This can be used by other clients or it no makes much sense ?

Thanks !