`appstreamcli search pdf` shows Okular. However, searching for PDF in Discover does not show it. It is in the appdata as shown https://invent.kde.org/graphics/okular/-/blob/master/shell/org.kde.okular.appdata.xml?ref_type=heads#L206 I believe it may be because it has several lines in the appdata and maybe Discover is only checking the first?
Can reproduce.
Duplicate? >>> https://bugs.kde.org/show_bug.cgi?id=499541
Similar, but not exactly the same. The term pdf is in the appstream data, for example Okular's <li>Supported Formats: PDF, PS, Tiff, DjVu, Images, DVI, XPS, Fiction Book, Comic Book, Plucker, EPub, Fax</li> <mediatype>application/pdf</mediatype> <mediatype>application/x-bzpdf</mediatype> <mediatype>application/x-gzpdf</mediatype> The linked bug is about the name of the application.