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="CareConnect-ReferralRequestMethod-1"/>
   <url value="https://fhir.hl7.org.uk/STU3/CodeSystem/CareConnect-ReferralRequestMethod-1"/>
   <version value="1.0.0"/>
   <name value="Care Connect Referral Request Method"/>
   <status value="draft"/>
   <date value="2019-07-16T17:43:00+00:00"/>
   <publisher value="HL7 UK"/>
   <description value="A CodeSystem to identify the form in which a referral is sent and received."/>
   <copyright value="Copyright © 2019 HL7 UK"/>
   <caseSensitive value="true"/>
   <content value="complete"/>
   <concept>
      <code value="1"/>
      <display value="Fax"/>
   </concept>
   <concept>
      <code value="2"/>
      <display value="Phone"/>
   </concept>
   <concept>
      <code value="3"/>
      <display value="Secure Messaging"/>
   </concept>
   <concept>
      <code value="4"/>
      <display value="Secure Email"/>
   </concept>
   <concept>
      <code value="5"/>
      <display value="Letter"/>
   </concept>
   <concept>
      <code value="6"/>
      <display value="NHS E-Referral Service"/>
   </concept>
   <concept>
      <code value="7"/>
      <display value="Self Referral"/>
   </concept>
</CodeSystem>