I've been hacking the Shadow4 skin to make it look better on high resolution laptop displays - it's too small for me on a 17" laptop at 1080p. I based my hack on "large calendar.xml" and it all seems to be working at least to my satisfaction.
When changing things, though, I noted an apparent inconsistency in the help file.
The description of the <today> tag says that it has <calendar> as a parent and that it has no attributes. However in the "today.xml" file in the Shadow4 skin the <today> tag doesn't have a parent and it does have attributes. Further, in the "today.xml" file its behaviour doesn't seem to match that given int the help file.
This isn't really a problem for me as, as I said, the hacked skin is doing what I want. More something that should be cleaned up eventually. Either that or my understanding of the descriptions isn't as good as I think.