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.
<CodeSystem xmlns="http://hl7.org/fhir">
<id value="CareConnect-NHSDataDictionary-PersonMaritalStatus-1"></id>
<text>
<status value="generated"></status>
</text>
<extension url="http://hl7.org/fhir/StructureDefinition/codesystem-sourceReference">
<valueUri value="http://www.datadictionary.nhs.uk/data_dictionary/attributes/p/person/person_marital_status_code_de.asp?shownav=1"></valueUri>
</extension>
<url value="https://fhir.hl7.org.uk/STU3/CodeSystem/CareConnect-NHSDataDictionary-PersonMaritalStatus-1"></url>
<version value="1.0.0"></version>
<name value="NHS Data Model and Dictionary Person Marital Status Code"></name>
<status value="active"></status>
<date value="2016-08-03T00:00:00+01:00"></date>
<publisher value="HL7 UK"></publisher>
<description value="An indicator to identify the legal marital status of a Person."></description>
<copyright value="Copyright © 2016 HL7 UK"></copyright>
<caseSensitive value="true"></caseSensitive>
<content value="complete"></content>
<concept>
<code value="S"></code>
<display value="Single"></display>
</concept>
<concept>
<code value="M"></code>
<display value="Married/Civil Partner"></display>
</concept>
<concept>
<code value="D"></code>
<display value="Divorced/Person whose Civil Partnership has been dissolved"></display>
</concept>
<concept>
<code value="W"></code>
<display value="Widowed/Surviving Civil Partner"></display>
</concept>
<concept>
<code value="P"></code>
<display value="Separated"></display>
</concept>
<concept>
<code value="N"></code>
<display value="Not disclosed"></display>
</concept>
</CodeSystem>