A few questions (possible typos?) re CSS2.1 4.1.1 - Tokenization and Appendix G

Sorry if asking about obvious things, but I have certain problems 
understanding the following aspects of CSS2.1 4.1.1 and Appendix G. Any 
advise will be appreciated.

1. 4.1.1 says:
"UNICODE-RANGE     U\+[0-9A-F?]{1,6}(-[0-9A-F]{1,6})?"
should the first question mark really be here? what would be the meaning 
of construct "U+A?6??C"? Also the fate of UNICODE-RANGE is not clear at 
all; it doesn't seem to be mentioned anywhere else in the document (if 
it is a legacy from CSS1, which seems the most likely guess, it would be 
a good thing to clarify it's potential use or uselessness).

2. Both 4.1.1 and Appendix G.2 say that 2nd (supposedly unquoted?) form 
of URI is described as follows:
"url\({w}([!#$%&*-~]|{nonascii}|{escape})*{w}\)"
some set of characters seems to be missing here; for example, I don't 
see how example from 4.3.4 ("url(http://www.example.com/redball.png)") 
can fit into this  description (as well as another description 
"url\({w}{string}{w}\)").

3. In G.2 YACC/FLEX grammar 'S' is defined as a single space ("[ 
\t\r\n\f]"), unlike 'S' in 4.1.1 ("[ \t\r\n\f]+"). While not a big deal, 
it looks a bit confusing.

Thanks in advance,
Sergey Ignatchenko