Wiki Page Templates
The default content for a new wiki page can be chosen from a list of page templates.
That list is made up from all the existing wiki pages having a name starting with PageTemplates/. The initial content of a new page will simply be the content of the chosen template page, or a blank page if the special (blank page) entry is selected. When there's actually no wiki pages matching that prefix, the initial content will always be the blank page and the list selector will not be shown (i.e. this matches the behavior we had up to now).
To create a new template, simply create a new page having a name starting with PageTemplates/.
(Hint: one could even create a PageTemplates/Template for facilitating the creation of new templates!)
See also: TracWiki