This is the root proto-page. The content of this form is ignored, but it’s fields are inherited by all other pages. E.g., if you were to set

actions = [[show_content = "wiki.show_content_as_lua_code"]]

on this page, all pages would default to displaying their content as if it was Lua code. (Note that any page that sets show_content to its own value, and any pages that inherit from it, will continue to work as they did before.) I.e., this page only affects the default values. Handle with care.