Aura.Component[] : Lightning Framework Specific Attributes Type

SK_AuraComponentAttributeApp.app

<aura:application extends="force:slds">
   <c:SK_AuraComponentAttributeUsageCmp/>
</aura:application>

SK_AuraComponentAttributeCmp.cmp

<aura:component >
    <aura:attribute name="ltngRegionName" type="String"/>
    <aura:attribute name="ltngCountriesList" type="Aura.Component[]">
        <!--To set a default value for type="Aura.Component[]", 
			put the default markup in the body of aura:attribute-->
        <ol class="slds-list--ordered">
            <li><b>US</b></li>
            <li><b>India</b></li>
        </ol>
    </aura:attribute>
    <!--Mark up which can be reused-->
    <div style="background-color:#E6E6FA;border-style: solid;height:100px;margin:2%;padding:1%;">
        <p>{!v.ltngRegionName} Countries List</p>
        {!v.ltngCountriesList}
    </div>
</aura:component>

SK_AuraComponentAttributeUsageCmp

<aura:component >
    <aura:attribute name="ltngAPACCountriesList" type="List" 
                    default="['India','Sri Lanka','Bangladesh']"/>
    <aura:attribute name="ltngEMEACountriesList" type="List" 
                    default="['France','Germany']"/>
    
    <c:SK_AuraComponentAttributeCmp ltngRegionName="Default">        
        <!--we are not setting ltngCountriesList attribute value so this will display 
		default body specified in SK_AuraComponentAttributeCmp--> 
    </c:SK_AuraComponentAttributeCmp>
    
    <c:SK_AuraComponentAttributeCmp ltngRegionName="APAC">
        <aura:set attribute="ltngCountriesList">
            <ol class="slds-list--ordered">
                <aura:iteration items="{!v.ltngAPACCountriesList}" var="country" >
                    <li><b>{!country}</b></li>
                </aura:iteration>
            </ol>
        </aura:set>
    </c:SK_AuraComponentAttributeCmp>
    
    <c:SK_AuraComponentAttributeCmp ltngRegionName="EMEA">        
        <aura:set attribute="ltngCountriesList">
            <ol class="slds-list--ordered">
                <aura:iteration items="{!v.ltngEMEACountriesList}" var="country" >
                    <li><b>{!country}</b></li>
                </aura:iteration>
            </ol>
        </aura:set>
    </c:SK_AuraComponentAttributeCmp>
    
</aura:component>