I am trying to export a complete subwiki (e.g. as a pdf). It seems to me like you can only export pages that are nested inside other pages, if you want to export multiple pages (except for the XAR-export). Is it possible to export a whole subwiki without making everything the nested page of one single page?
Indeed this is not supported currently. I couldn’t find an issue about it, feel free to create one at https://jira.xwiki.org
Note: We used to be able to pass pages query string parameters to list several page (see https://www.xwiki.org/xwiki/bin/view/Documentation/UserGuide/Features/Exports#HAdvanced-2) in the server-side PDF export. However, we’ve lost this feature in the new PDF export application (client-side-based one). See Loading...
In short, currently the only export feature that is wiki-wide is the XAR export. However it’s possible with the HTML export, see Loading.... I don’t remember if using wildcards was possible with the server-side PDF export query string options but I don’t think so.
Right now, what you can do is create a page to perform the PDF export using a script, see https://extensions.xwiki.org/xwiki/bin/view/Extension/PDF%20Export%20Application/#HScriptService There you can specify all the pages to export.