A list of issues is just multiple IssueDetail elements wrapped in an IssuesList element.

The IssueSearch and IssueList resources both return IssueList responses.

Sample

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<?xml version="1.0" encoding="utf-8"?>
<IssuesList>
  <IssueDetails>
    <Fields>
      <IssueId>589</IssueId>
    </Fields>
    <Attachments>
      <Attachment>
        <AttachmentId>259</AttachmentId>
        <AttachmentFilename>a.txt</AttachmentFilename>
        <AttachmentMimeType>text/plain</AttachmentMimeType>
      </Attachment>
    </Attachments>
    <Subscribers>
      <Subscriber>
        <SubscribersUserId>Administrator</SubscribersUserId>
        <SubscribersSendEMail>True</SubscribersSendEMail>
      </Subscriber>
    </Subscribers>
    <Histories>
      <History>
        <HistoryId>1603</HistoryId>
        <HistoryCreatedByUserId>Administrator</HistoryCreatedByUserId>
        <HistoryCreatedOn>2009-01-11T16:21:43.797Z</HistoryCreatedOn>
        <HistoryNewResolutionCode>New</HistoryNewResolutionCode>
        <HistoryNewStatusCode>Open</HistoryNewStatusCode>
        <HistoryNewAssignedToUserId>jqa</HistoryNewAssignedToUserId>
        <HistoryOldResolutionCode />
        <HistoryOldStatusCode />
        <HistoryOldAssignedToUserId />
      </History>
    </Histories>
    <IssueDetails>
      <Fields>
        <IssueId>5</IssueId>
      </Fields>
      <Histories>
        <History>
          <HistoryId>3</HistoryId>
          <HistoryCreatedByUserId>jqa</HistoryCreatedByUserId>
          <HistoryCreatedOn>2008-11-30T14:41:30.727Z</HistoryCreatedOn>
          <HistoryNewResolutionCode>New</HistoryNewResolutionCode>
          <HistoryNewStatusCode>Open</HistoryNewStatusCode>
          <HistoryNewAssignedToUserId>jpmsr</HistoryNewAssignedToUserId>
          <HistoryOldResolutionCode />
          <HistoryOldStatusCode />
          <HistoryOldAssignedToUserId />
        </History>
      </Histories>
      <IssueDetails>
        <Fields>
          <IssueId>4</IssueId>
        </Fields>
        <Histories>
          <History>
            <HistoryId>2</HistoryId>
            <HistoryCreatedByUserId>jqa</HistoryCreatedByUserId>
            <HistoryCreatedOn>2008-11-30T14:37:07.193Z</HistoryCreatedOn>
            <HistoryNewResolutionCode>New</HistoryNewResolutionCode>
            <HistoryNewStatusCode>Open</HistoryNewStatusCode>
            <HistoryNewAssignedToUserId>jqasr</HistoryNewAssignedToUserId>
            <HistoryOldResolutionCode />
            <HistoryOldStatusCode />
            <HistoryOldAssignedToUserId />
          </History>
        </Histories>
        <IssueDetails>
          <Fields>
            <IssueId>3</IssueId>
          </Fields>
          <Histories>
            <History>
              <HistoryId>1</HistoryId>
              <HistoryCreatedByUserId>jpm</HistoryCreatedByUserId>
              <HistoryCreatedOn>2008-11-30T14:34:48.333Z</HistoryCreatedOn>
              <HistoryNewResolutionCode>New</HistoryNewResolutionCode>
              <HistoryNewStatusCode>Open</HistoryNewStatusCode>
              <HistoryNewAssignedToUserId>jpmsr</HistoryNewAssignedToUserId>
              <HistoryOldResolutionCode />
              <HistoryOldStatusCode />
              <HistoryOldAssignedToUserId />
            </History>
            <History>
              <HistoryId>1604</HistoryId>
              <HistoryCreatedByUserId>Administrator</HistoryCreatedByUserId>
              <HistoryCreatedOn>2009-01-11T16:21:00Z</HistoryCreatedOn>
              <HistoryNewResolutionCode>New</HistoryNewResolutionCode>
              <HistoryNewStatusCode>Open</HistoryNewStatusCode>
              <HistoryNewAssignedToUserId>jpmsr</HistoryNewAssignedToUserId>
              <HistoryOldResolutionCode>New</HistoryOldResolutionCode>
              <HistoryOldStatusCode>Open</HistoryOldStatusCode>
              <HistoryOldAssignedToUserId>jpmsr</HistoryOldAssignedToUserId>
            </History>
          </Histories>
        </IssueDetails>
      </IssueDetails>
    </IssueDetails>
  </IssueDetails>
</IssuesList>

Schema

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<!--
  IssuesList 
    - A list of IssueDetails (possibly empty)
-->
<xs:element name="IssuesList">
  <xs:complexType>
    <xs:sequence minOccurs="0" maxOccurs="unbounded">
      <xs:element ref="IssueDetails" />
    </xs:sequence>
  </xs:complexType>
</xs:element>

<!--
  IssueDetails
    - The XML message definition returned to describe an existing issue
-->
<xs:element name="IssueDetails">
  <xs:complexType>
    <xs:all>
      <xs:element name="Fields" minOccurs="0" maxOccurs="1">
        <xs:complexType>
          <xs:sequence minOccurs="1" maxOccurs="unbounded">
            <xs:any processContents="skip" />
          </xs:sequence>
        </xs:complexType>
      </xs:element>
      <xs:element name="Comments" minOccurs="0" maxOccurs="1">
        <xs:complexType>
          <xs:sequence minOccurs="1" maxOccurs="unbounded">
            <xs:element name="Comment">
              <xs:complexType>
                <xs:all>
                  <xs:element name="CommentId" type="xs:integer" />
                  <xs:element name="CommentAuthorUserId" type="xs:string" />
                  <xs:element name="CommentCreatedOn" type="xs:dateTime" />
                  <xs:element name="CommentField" type="xs:string" />
                  <xs:element name="CommentText" type="xs:string" />
                </xs:all>
              </xs:complexType>
            </xs:element>
          </xs:sequence>
        </xs:complexType>
      </xs:element>
      <xs:element name="Attachments" minOccurs="0" maxOccurs="1">
        <xs:complexType>
          <xs:sequence minOccurs="1" maxOccurs="unbounded">
            <xs:element name="Attachment">
              <xs:complexType>
                <xs:all>
                  <xs:element name="AttachmentId" type="xs:integer" />
                  <xs:element name="AttachmentFilename" type="xs:string" />
                  <xs:element name="AttachmentMimeType" type="xs:string" />
                  <xs:element name="AttachmentData" type="xs:string" />
                </xs:all>
              </xs:complexType>
            </xs:element>
          </xs:sequence>
        </xs:complexType>
      </xs:element>
      <xs:element name="RelatedIssues" minOccurs="0" maxOccurs="1">
        <xs:complexType>
          <xs:sequence minOccurs="1" maxOccurs="unbounded">
            <xs:element name="RelatedIssueId" type="xs:integer" />
          </xs:sequence>
        </xs:complexType>
      </xs:element>
      <xs:element name="RelatedItems" minOccurs="0" maxOccurs="1">
        <xs:complexType>
          <xs:sequence minOccurs="1" maxOccurs="unbounded">
            <xs:element name="RelatedItem">
              <xs:complexType>
                <xs:all>
                  <xs:element name="RelatedItemId" type="xs:integer" />
                  <xs:element name="RelatedItemUrl" type="xs:string" />
                  <xs:element name="RelatedItemTitle" type="xs:string" />
                  <xs:element name="RelatedItemOpenInNewWindow" type="xs:boolean" />
                </xs:all>
              </xs:complexType>
            </xs:element>
          </xs:sequence>
        </xs:complexType>
      </xs:element>
      <xs:element name="Subscribers" minOccurs="0" maxOccurs="1">
        <xs:complexType>
          <xs:sequence minOccurs="1" maxOccurs="unbounded">
            <xs:element name="Subscriber">
              <xs:complexType>
                <xs:all>
                  <xs:element name="SubscriberUserId" type="xs:string" />
                  <xs:element name="SubscriberSendEMail" type="xs:boolean" />
                </xs:all>
              </xs:complexType>
            </xs:element>
          </xs:sequence>
        </xs:complexType>
      </xs:element>
      <xs:element name="Histories" minOccurs="0" maxOccurs="1">
        <xs:complexType>
          <xs:sequence minOccurs="1" maxOccurs="unbounded">
            <xs:element name="History">
              <xs:complexType>
                <xs:all>
                  <xs:element name="HistoryId" type="xs:integer" />
                  <xs:element name="HistoryCreatedByUserId" type="xs:string" />
                  <xs:element name="HistoryCreatedOn" type="xs:dateTime" />
                  <xs:element name="HistoryNewResolutionCode" type="xs:string" />
                  <xs:element name="HistoryNewStatusCode" type="xs:string" />
                  <xs:element name="HistoryNewAssignedToUserId" type="xs:string" />
                  <xs:element name="HistoryOldResolutionCode" type="xs:string" />
                  <xs:element name="HistoryOldStatusCode" type="xs:string" />
                  <xs:element name="HistoryOldAssignedToUserId" type="xs:string" />
                  <xs:element name="HistoryChangeDetails" type="xs:string" />
                </xs:all>
              </xs:complexType>
            </xs:element>
          </xs:sequence>
        </xs:complexType>
      </xs:element>
    </xs:all>
  </xs:complexType>
</xs:element>