I would like to customize the default menubar_related_categories.tpl and put it in my template-extension directory. However, there is no Original menubar_related_categories.tpl listed under Configuration >> Templates which I could bind it to. All my other customized templates are listed, but not this one.

Right now I need to directly modify the original file in themes/default/template/, and that works fine. However, modifying that file will not survive upgrades to Piwigo, unlike those in template-extension/ .

Any suggestions how to get menubar_related_categories.tpl included in the list of Original templates?