This has been reported on many different distributions, it seems that since this change:
Browsers like firefox and chromium are unable to play .swf videos but, instead, they try to download the file but, then, I cannot find any application ready to open them :/
You can see people are workarounding this issue reverting the change:
But that doesn't seem really "clean" to me :/
Thanks a lot for your help
If your browser can't handle aliases, then they're the broken ones, sorry.
Looks like the browser plugin expects an old mime-type, which the browser won't give it. The browser could lie to the plugin when it sees it supports an alias.
In any case, not a problem with the definition. I suggest you file a bug against the separate browsers.
They are reported for a long time... but nothing is done on their side :(