eHealth Infrastructure (v2020.4) 

{
  "resourceType" : "OperationDefinition",
  "id" : "Binary--retrieve-document",
  "text" : {
    "status" : "generated",
    "div" : "<div xmlns=\"http://www.w3.org/1999/xhtml\"><h2>retrieve-document</h2><p>OPERATION: retrieve-document</p><p>The official URL for this operation definition is: </p><pre>http://ehealth.sundhed.dk/fhir/OperationDefinition/Binary--retrieve-document</pre><div><p>Retrieve document.</p>\n</div><p>URL: [base]/Binary/$retrieve-document</p><p>Parameters</p><table class=\"grid\"><tr><td><b>Use</b></td><td><b>Name</b></td><td><b>Cardinality</b></td><td><b>Type</b></td><td><b>Binding</b></td><td><b>Documentation</b></td></tr><tr><td>IN</td><td>url</td><td>1..1</td><td><a href=\"http://hl7.org/fhir/STU3/datatypes.html#string\">string</a><br/>(<a href=\"http://hl7.org/fhir/STU3/search.html#uri\">uri</a>)</td><td/><td/></tr><tr><td>OUT</td><td>return</td><td>0..1</td><td><a href=\"http://hl7.org/fhir/STU3/binary.html\">Binary</a></td><td/><td/></tr></table></div>"
  },
  "url" : "http://ehealth.sundhed.dk/fhir/OperationDefinition/Binary--retrieve-document",
  "name" : "retrieve-document",
  "status" : "active",
  "kind" : "operation",
  "date" : "2020-05-22T12:11:22+00:00",
  "description" : "Retrieve document.",
  "idempotent" : true,
  "code" : "retrieve-document",
  "resource" : [
    "Binary"
  ],
  "system" : false,
  "type" : true,
  "instance" : false,
  "parameter" : [
    {
      "name" : "url",
      "use" : "in",
      "min" : 1,
      "max" : "1",
      "type" : "string",
      "searchType" : "uri"
    },
    {
      "name" : "return",
      "use" : "out",
      "min" : 0,
      "max" : "1",
      "type" : "Binary"
    }
  ]
}