This is a HL7 FHIR server, and as you appear to be accessing this page from a web browser you are seeing a HTML version of the requested resource(s). You can also access this URL from a FHIR client as a ReSTful API call. For more details please see the HL7 FHIR specification.
{
  "resourceType": "CodeSystem",
  "id": "CareConnect-RegistrationType-1",
  "url": "https://fhir.hl7.org.uk/STU3/CodeSystem/CareConnect-RegistrationType-1",
  "version": "1.0.0",
  "name": "Care Connect Registration Type",
  "status": "draft",
  "date": "2017-08-01T00:00:00+00:00",
  "publisher": "HL7 UK",
  "description": "A CodeSystem that identifies the type of registration for a patient at a healthcare organisation.",
  "copyright": "Copyright © 2016 HL7 UK",
  "caseSensitive": true,
  "content": "complete",
  "concept": [
    {
      "code": "R",
      "display": "Regular"
    },
    {
      "code": "E",
      "display": "Emergency"
    },
    {
      "code": "IN",
      "display": "Immediately necessary"
    },
    {
      "code": "T",
      "display": "Temporary"
    },
    {
      "code": "P",
      "display": "Private"
    },
    {
      "code": "O",
      "display": "Other"
    },
    {
      "code": "S",
      "display": "Synthetic Record"
    }
  ]
}