[CSS21] 15.3 font-family: undefined keywords

Section 15.3 Font family:
<http://www.w3.org/TR/CSS2/fonts.html#font-family-prop>  the 'font-family'
property says:

Font family names that happen to be the same as a keyword value (e.g.
'initial', 'inherit', 'default', 'serif', 'sans-serif', 'monospace',
'fantasy', and 'cursive') must be quoted to prevent confusion with the
keywords with the same names.

However, the keywords 'initial', 'default' are undefined, neither under
Assigning property values, <http://www.w3.org/TR/CSS2/cascade.html>
Cascading, and Inheritance nor here.  Internet Explorer does not support
them and initial <https://developer.mozilla.org/En/CSS/Initial>  |
-moz-initial - MDC says 'initial' belongs to CSS3.

I recommend not mentioning those keywords here to prevent confusion.

By the way, do inherited and overridden font family declarations get
appended to the font set?  By [CSS21]
<http://lists.w3.org/Archives/Public/www-style/2005Mar/0121.html>
font-family: inheritance and missing fonts from Christian Roth on 2005-03-23
(www-style@w3.org from March 2005), IE5 appends, IE6 replaces, and my
observation is that IE8 appends again, so I am lost.  Additionally, there is
no test for the font matching algorithm at the CSS
<http://www.w3.org/Style/CSS/Test/CSS2.1/current/html4/by-section.htm>  2.1
Test Suite: Index by Section, so it is really hard to tell.

Thanks in advance,

Chris