An 'undefined' page is any page that has been linked to from within Confluence, but that does not yet exist.

Undefined Page Linked From
unknown Page: Build Configuration Template (TeamCity 9.x Documentation)
Page: Assigning Build Configurations to Specific Build Agents (TeamCity 9.x Documentation)
Page: Favorite Build (TeamCity 9.x Documentation)
Page: Custom Notifier (TeamCity 9.x Documentation)
Page: ClearCase (TeamCity 9.x Documentation)
and approximately 18 more…