class AliasPluginModel(CMSPlugin): cmsplugin_ptr = models.OneToOneField( CMSPlugin, on_delete=models.CASCADE, related_name='cms_aliasplugin', parent_link=True, ) plugin = models.ForeignKey( CMSPlugin, on_delete=models.CASCADE, editable=False, related_name='alias_reference', null=True, ) alias_placeholder = models.ForeignKey( Placeholder, on_delete=models.CASCADE, editable=False, related_name='alias_placeholder', null=True, ) class Meta: app_label = 'cms

The AliasPluginModel is a subclass of CMSPlugin and it has a one-to-one relation with CMSPlugin.
It also has a foreign key relation with CMSPlugin and a foreign key relation with Placeholder.