This is fixed as of Firefox 63.0. One can't specify the file type anymore and typing 'test.pdf' and clicking 'Select' now simply opens the folder and then clears the 'Name' field for saving as a file.
This is fixed as of Firefox 63.0. One can't specify the file type anymore and typing 'test.pdf' and clicking 'Select' now simply opens the folder and then clears the 'Name' field for saving as a file.