headers in agentless REST API

Document gievs following

Headers

A dialog box opens with two boxes. For the Header key, enter data as free text. For the Header value, select one of the following options:

  • Simple Mode. Enter the required data manually.
  • Expression Language. Enter an Expression Language phrase that returns the required data.

Click Add item to add an additional row with boxes for another header.

The REST call request headers provide additional information for the REST call, such as the file type to be returned.

Note If not specified, the following values are used for Headers:
  • Accept: application/json
  • Content-Type: application/json

You must explicitly specify Headers if the default values don't work for you. 

However it is not clear the exact required syntax for this 

For example if there are multiple header including defafult one. In such can I presume that default headers will be there or since I am going to specify hence I have to specify default headers explicitly.

Does each headers entered as a separate entry?

Should header name enclosed in single quotes or any specific delimiter?

Should value for each header be enclosed in single quote or any delimiter?

Unfortunately document does not given any example for this.

Best regards,

Uday Joshi