Board Thread:Support Requests - Community Management/@comment-166057-20130804174916/@comment-1330470-20130805021006

The wording of "add a graphic" is a bit misleading, 'cause it leads to Special:Upload, which is the general upload page that permits more than just graphics to be uploaded (though graphics make up 99% of the use).

PDF upload would be via that page, as would be TXT and XLS upload if you enabled it. The page lists permitted file types: a few extra ones are enabled on Central, but the default list appears to be...
 * "png, gif, jpg, jpeg, ico, pdf, svg, odt, ods, odp, odg, odc, odf, odi, odm, ogg, ogv, oga."