A transclusion box is a handle, typically only available to users who actually have write access to a page, to quickly jump to the page from which content is transcluded.
The rendering can be controlled via space propertyrender-transclusion-box.
The following values are valid:
only-with-edit-permission
The reference box is only rendered, if the user has edit permission. That is the user is an other and benefits from the clue of transcluded content.
never
The reference box is never rendered. This may proof useful for authors that want to check the appearance without boxes.