Thread:Project:Support desk/sidebar is deleted/reply (2)

When a MediaWiki message has been deleted, it just means that the message has been restored to its default version. Edits to the page are simply customizations of the messages that differ from the default version. If you want to edit the sidebar, just edit the associated mediawiki message at MediaWiki:Sidebar, and you do not have to worry about whether it is deleted or not. The full list of messages can be found at Special:AllMessages, along with the difference between the default messages and the customized messages.