The following wiki pages provide special functionality.
Underscores in Wiki Names
Wikis whose names start with an underscore (for example: "_hiddenPage") do not appear in the wiki table of contents, for non-admin users. For admin users, the pages are visible in the table of contents.
A wiki page named "_header" will replace the default "LabKey Server" logo and header. Adding the _header wiki to a project means it will be applied to all of the folders within that project.