Can you add a comment here to distinguish uploadLimit from uploadMaxFilesize ?
From reading this here it's still a bit confusing.
From my understanding `uploadLimit` is the PHP upload limit and `uploadMaxFileSize` is the combination of free space and uploadLimit.

Maybe later we can remove 'uploadMaxFilesize' and compute it in the client side. From grepping the code it looks like a bigger change, so let's leave it for now and just add comments to clarify.