The only allowed child elements of `<p>` are `<em>` and `<code>`: https://www.freedesktop.org/software/appstream/docs/chap-Metadata.html#tag-description Spotted in https://gitlab.gnome.org/GNOME/gnome-software/-/issues/2154 Signed-off-by: Philip Withnall <pwithnall@endlessos.org> Fixes: #1012