Unicode URI considerations

URLs must be compatible with the DNS system.
Therefore they are restricted to ASCII set characters.

To make Chinese URLs, for example, a system of representing the thousands of available characters is to use ascii character to represent their character codes. Such encodings use the % sign within the context, but probably not at the end of content. This could of course be used to obfusticate all sorts of things. IE7 and Opera show Punicode chars - transport in ascii but client representation in local unicode equivalents. Therefore we can not build the data or edit with Firefox at all?