The "/wikiedit" page:

The main front-end for the Ajax-based wiki editor app. Passing in the name of an unknown page will trigger the creation of a new page (which is not actually created in the database until the user explicitly saves it). If passed no page name, the user may select a page from the list on the first UI tab.

When creating a new page, the mimetype URL parameter may optionally be used to set its mimetype to one of text/x-fossil-wiki, text/x-markdown, or text/plain, defaulting to the former.