This Lua module is used in system messages. Changes to it can cause immediate changes to the Wikipedia user interface. To avoid major disruption, any changes should be tested in the module's /sandbox or /testcases subpages, or in your own module sandbox. The tested changes can be added to this page in a single edit. Please discuss changes on the talk page before implementing them.
This module implements title suggestions for the "Bad title" interface message at MediaWiki:Title-invalid-characters. When the user asks for a page with invalid characters, this module checks for a page with the given title up to the first invalid character. If it exists, {{Did you mean box}} is displayed.