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": "ConceptMap",
  "id": "CareConnect-AllergyVerificationStatus-1",
  "url": "https://fhir.hl7.org.uk/STU3/ConceptMap/CareConnect-AllergyVerificationStatus-1",
  "version": "1.1.0",
  "name": "Concept Map - Allergy Verification Status",
  "status": "draft",
  "date": "2018-11-14T00:00:00+00:00",
  "publisher": "HL7 UK",
  "description": "A Concept Map from ValueSet Allergy Verification Status to Allergy Certainity to aid interpretation.",
  "copyright": "Copyright © 2016 HL7 UK",
  "sourceReference": {
    "reference": "https://fhir.hl7.org.uk/STU3/ValueSet/CareConnect-AllergyVerificationStatus-1"
  },
  "targetReference": {
    "reference": "https://fhir.hl7.org.uk/STU3/ValueSet/CareConnect-AllergyCertainty-1"
  },
  "group": [
    {
      "source": "http://hl7.org/fhir/allergy-verification-status",
      "target": "http://snomed.info/sct",
      "element": [
        {
          "code": "unconfirmed",
          "display": "Unconfirmed",
          "target": [
            {
              "code": "385434005",
              "display": "Improbable diagnosis",
              "equivalence": "equivalent"
            }
          ]
        },
        {
          "code": "unconfirmed",
          "display": "Unconfirmed",
          "target": [
            {
              "code": "2931005",
              "display": "Probable diagnosis",
              "equivalence": "equivalent"
            }
          ]
        },
        {
          "code": "confirmed",
          "display": "Confirmed",
          "target": [
            {
              "code": "255545003",
              "display": "Definite",
              "equivalence": "equivalent"
            }
          ]
        },
        {
          "code": "confirmed",
          "display": "Confirmed",
          "target": [
            {
              "code": "410605003",
              "display": "Confirmed present",
              "equivalence": "equivalent"
            }
          ]
        }
      ]
    }
  ]
}