OK Let’s try SVG and see if that works.
The extension SVG is not allowed.
Let’s try 7-Zip
Tracker Post in IE7.7z
OK
PDF: The extension pdf is not allowed.
WMF: The extension wmf is not allowed.
HTML: The extension html is not allowed.
The upload was rejected because the uploaded file was identified as a possible attack vector.
APNG:
basketball1.png
OK
TXT: The extension text is not allowed. (Surprising).
Animated GIF:
BowingBhikkhu.gif
OK