In about:config
I've set extensions.firebug.cache.mimeTypes
to a space-separated list of MIME types, restarted Firefox, and everything got saved.
application/x-shockwave-flash image/gif image/jpeg image/png application/octet-stream
Please note that some documents are still missing from the .har
file, I get this:
Reload the page to get source for: http://...