PDF with embedded OpenDocument

Uploading a PDF which has an OpenDocument embedded, a feature of LibreOffice (see attached), results in error:

The file is a corrupt or otherwise unreadable ZIP file. It cannot be properly checked for security. (error code bad-zip)

$ file test-embedded-opendocument.pdf
test-embedded-opendocument.pdf: PDF document, version 1.4

$ unzip test-embedded-opendocument.pdf
Archive: test-embedded-opendocument.pdf
warning [test-embedded-opendocument.pdf]: 481 extra bytes at beginning or within zipfile

(attempting to process anyway)

extracting: mimetype
extracting: Thumbnails/thumbnail.png

inflating: styles.xml              
inflating: content.xml             
inflating: meta.xml                
inflating: settings.xml            
inflating: manifest.rdf            
inflating: Configurations2/accelerator/current.xml  
 creating: Configurations2/progressbar/
 creating: Configurations2/statusbar/
 creating: Configurations2/images/Bitmaps/
 creating: Configurations2/floater/
 creating: Configurations2/toolbar/
 creating: Configurations2/popupmenu/
 creating: Configurations2/toolpanel/
 creating: Configurations2/menubar/
inflating: META-INF/manifest.xml

It would be reasonable to detect this as a ZIP or an OpenDocument instead of a PDF, and only allow upload if the mime type if permitted (which it isnt, on WMF projects at least due to bug 2089), but it should have a nice informative error message as this is a file type we'll seeing an increasing number of, and it is readable as a PDF in all programs I've tried it on.

Version: unspecified
Severity: enhancement
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=31930
https://bugzilla.wikimedia.org/show_bug.cgi?id=2089

Attached: