What are the Mozilla file upload naming requirements?

Question

Mozilla Firefox

I came across the fact that the mozilla cuts off the name of the saved file by the first space, and discards the rest.
Then I looked through all the top names of the saved files, such as "skype, google chrome, steam, virtual box" they all do not have spaces, or they have underscores to separate them.
Isn't this all easy? And Mozilla has some rules/requirements??

Answer 1

And who will monitor the observance of the URL format for you and encode all characters, except for a very limited set, in URL encoding, that is, for the same space -% 20, and so on? Well, in general, even if a space is supported by some OS in file names, this is bad form for data that is hosted on the network.

Answer 2

what platform?
what mozilla?
what file system?
Mozilla doesn't really care. It's not all the same to the http protocol, whose urls don't like spaces and replace them with %20.