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.
<?xml version="1.0" encoding="UTF-8" standalone="no"?><CodeSystem xmlns="http://hl7.org/fhir">
   <id value="GPConnect-SecondaryListValues-1"/>
   <url value="https://fhir.hl7.org.uk/STU3/CodeSystem/GPConnect-SecondaryListValues-1"/>
   <version value="1.0.0"/>
   <name value="GPConnect Secondary List Values"/>
   <status value="active"/>
   <date value="2020-09-25T17:21:47+00:00"/>
   <publisher value="HL7 UK"/>
   <description value="A CodeSystem to identify the secondary list values."/>
   <copyright value="Copyright © 2020 HL7 UK"/>
   <caseSensitive value="true"/>
   <content value="complete"/>
   <concept>
      <code value="consultations-allergies-contained-in-consultations"/>
      <display value="Consultations - allergies contained in consultations"/>
   </concept>
   <concept>
      <code value="consultations-allergies-that-have-been-ended-contained-in-consultations"/>
      <display value="Consultations - allergies that have been ended contained in consultations"/>
   </concept>
   <concept>
      <code value="consultations-diary-entries-contained-in-consultations"/>
      <display value="Consultations - diary entries contained in consultations"/>
   </concept>
   <concept>
      <code value="consultations-documents-contained-in-consultations"/>
      <display value="Consultations - documents contained in consultations"/>
   </concept>
   <concept>
      <code value="consultations-immunisations-contained-in-consultations"/>
      <display value="Consultations - immunisations contained in consultations"/>
   </concept>
   <concept>
      <code value="consultations-investigations-contained-in-consultations"/>
      <display value="Consultations - investigations contained in consultations"/>
   </concept>
   <concept>
      <code value="consultations-medications-contained-in-consultations"/>
      <display value="Consultations - medications contained in consultations"/>
   </concept>
   <concept>
      <code value="consultations-outbound-referrals-in-consultations"/>
      <display value="Consultations - outbound referrals in consultations"/>
   </concept>
   <concept>
      <code value="consultations-problems-contained-in-consultations"/>
      <display value="Consultations - problems contained in consultations"/>
   </concept>
   <concept>
      <code value="consultations-uncategorised-data-contained-in-consultations"/>
      <display value="Consultations - uncategorised data contained in consultations"/>
   </concept>
   <concept>
      <code value="problems-allergies-related-to-problems"/>
      <display value="Problems - allergies related to problems"/>
   </concept>
   <concept>
      <code value="problems-allergies-that-have-been-ended-related-to-problems"/>
      <display value="Problems - allergies that have been ended related to problems"/>
   </concept>
   <concept>
      <code value="problems-consultations-related-to-problems"/>
      <display value="Problems - consultations related to problems"/>
   </concept>
   <concept>
      <code value="problems-diary-entries-related-to-problems"/>
      <display value="Problems - diary entries related to problems"/>
   </concept>
   <concept>
      <code value="problems-documents-related-to-problems"/>
      <display value="Problems - documents related to problems"/>
   </concept>
   <concept>
      <code value="problems-immunisations-related-to-problems"/>
      <display value="Problems - immunisations related to problems"/>
   </concept>
   <concept>
      <code value="problems-investigations-related-to-problems"/>
      <display value="Problems - investigations related to problems"/>
   </concept>
   <concept>
      <code value="problems-medications-related-to-problems"/>
      <display value="Problems - medications related to problems"/>
   </concept>
   <concept>
      <code value="problems-outbound-referrals-related-to-problems"/>
      <display value="Problems - outbound referrals related to problems"/>
   </concept>
   <concept>
      <code value="problems-linked-problems-not-relating-to-the-primary-query"/>
      <display value="Problems - linked problems not relating to the primary query"/>
   </concept>
   <concept>
      <code value="problems-uncategorised-data-related-to-problems"/>
      <display value="Problems - uncategorised data related to problems"/>
   </concept>
</CodeSystem>