Thread:Support/Sidebar in japanese in TWN

Hi. In Japanese, the sidebar in TWN links to mainpage, community portal, recent events, recent changes.... For example, in de, the sidebar links to Special:LanguageStats, Portal:De, recent changes, Translating:Languages.... I prefer the sidebar as de, so I want to edit MediaWiki:Sidebar or somewhere, but I don't know where should be edited. Could you tell me about the sidebar in TWN?