It does, but something is malformed when it comes from savefrom.net, therefore, after upload, Twitter will not process it like it does other mp4 videos from other sources.

It is something though that is in savefrom's formatting, all other FB downloader sites I have used export files that work with Twitter when you upload them, the file uploads OK but Twitter tells you it can't process that formatting of the mp4 file you got from savefrom.netm then refuses to post it.

No, After I downloaded from Facebook I uploaded the file to Twitter, Twitter would not accept the file savefrom.net generated.