I'm not sure this attribute makes sense. Yes you can specify a set of types to only allow but this is then used in the file system's native browser to simply filter files out and it clearly shows the user what it's looking for.

For file size there is no interface that shows you what your limit or acceptable range is. In this case how do you notify the user they're trying to upload more than they should? Do we then tie modals / messages to the file input to handle the cases where a user selects something too big?

At least right now you can handle all of this via JavaScript. I think that may make sense to continue versus adding additional attributes.