Q: How do I update an attribute label for a custom community content layout theme? When creating a custom component you often add attributes. You can then specify a label for these attributes that shows up in the community builder by specifying it in the components design resource.
I expected this to work similiarly when creating creating a custom content layout for communities. However, I can not figure out how to update the label for attributes which have the type:
Aura.component[]

I can update the label of the entire theme, so when selecting it in the community builder it looks as expected, but I cannot figure this out for an individual section. I specifically want a name that includes a space, hence why just having it as the name attribute will not do. 
My code is similar to what follows:
Component:
<aura:component implements="forceCommunity:layout" description="Custom Layout" access="global">
<aura:attribute name="ContentHeader" type="Aura.Component[]" required="false" />
    <div class="slds-container_large">
        <div class="slds-grid slds-grid_vertical">
            <div class="slds-col">{!v.ContentHeader}</div>
        </div>
    </div>
</aura:component>

Design Resource:
<design:component label="Single Column, Containerised Content Layout">
    <!-- would put a design:attribute here, but it complains that only types of int, string and boolean are support -->
</design:component>

The out-of-the-box layout components have sections titled Content Header, Content Footer etc, so I would think this should be possible. 
How can I create a content layout theme with sections labeled with spaces?
