Oh, what I actually suggest is removing Toolbox#Adding a List of Sub-Pages.
The section "Adding a List of Sub-Pages" is on the English page, so shouldn't be removed from translated pages. I thought I was removing Toolbox_(zh_TW)/子頁面示範 because it is old-style translation, which is replaced by the (partly translated) Toolbox/zh-tw page.
I want to delete both the English section and all of its translation. Currently only zh_TW is translated.
Thinking more about your request, it has been decided that tools like this, that are mainly useful for maintenance tasks, should be moved out of normal 'user' pages. We will create a page for admin tools, and this tool will be one of the first to be migrated there. It may take a few days for it to happen, but we won't forget.