I was trying to upload a file with an existing filename (to test the user-warning message).
The warning template is broken.
Unknown warning: "{"upload":{"result":"Warning","warnings":{"exists-normalized":"Pixies-Doolittle.png"},"filekey":"13x9lgznmpi4.6u1hq5.3099303.jpg","sessionkey":"13x9lAdditionally, I checked against a filename that is protected ("example"), and a filename that was previously deleted ("screenshot"), and those are both also broken.
(Firefox, Ubuntu. Tested at https://en.wikipedia.org/wiki/User:Quiddity_%28WMF%29/sandbox )


