http://hl7.org/fhir/StructureDefinition/humanname-partner-name|5.2.0

The portion of the family name that is derived from the person's partner's surname, as distinguished from any portion that is derived from the surname of the person's own name.
{
  "description": "The portion of the family name that is derived from the person's partner's surname, as distinguished from any portion that is derived from the surname of the person's own name.",
  "package": "hl7.fhir.uv.extensions.r4@5.2.0",
  "date": "2015-11-22T00:00:00Z",
  "derivation": "constraint",
  "publisher": "HL7 International / FHIR Infrastructure",
  "fhirVersion": "4.0.1",
  "jurisdiction": [ {
    "coding": [ {
      "code": "001",
      "system": "http://unstats.un.org/unsd/methods/m49/m49.htm"
    } ]
  } ],
  "name": "PartnerName",
  "mapping": [ {
    "uri": "http://hl7.org/v2",
    "name": "HL7 v2 Mapping",
    "identity": "v2"
  }, {
    "uri": "http://hl7.org/v3",
    "name": "RIM Mapping",
    "identity": "rim"
  } ],
  "abstract": false,
  "type": "Extension",
  "experimental": false,
  "resourceType": "StructureDefinition",
  "fhirversion": null,
  "title": "Partner Name",
  "versionAlgorithmCoding": null,
  "extension": [ {
    "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-wg",
    "valueCode": "fhir"
  }, {
    "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm",
    "valueInteger": 3
  }, {
    "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status",
    "valueCode": "trial-use"
  }, {
    "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-type-characteristics",
    "valueCode": "can-bind"
  } ],
  "status": "active",
  "id": "608fabec-098e-52d3-8e1c-72332033eceb",
  "kind": "complex-type",
  "url": "http://hl7.org/fhir/StructureDefinition/humanname-partner-name",
  "identifier": [ {
    "value": "urn:oid:2.16.840.1.113883.4.642.5.1641",
    "system": "urn:ietf:rfc:3986"
  } ],
  "context": [ {
    "type": "element",
    "expression": "HumanName.family"
  } ],
  "versionAlgorithmString": null,
  "fhir_id": null,
  "version": "5.2.0",
  "contact": [ {
    "telecom": [ {
      "value": "http://www.hl7.org/Special/committees/fiwg",
      "system": "url"
    } ]
  } ],
  "baseDefinition": "http://hl7.org/fhir/StructureDefinition/Extension"
}