Valid place="" are ActiveWindow, InactiveWindow, MenuTitle, and MenuItem.
Only valid weight is "bold"
Valid slants are "italic" and "oblique"
shadowTint is a value between -100 and 100
size is the font size in points. pixelsize could possibly be added in the form of 8px, but it's not right now.
the name can contain multiple families and they will all be used to match characters
You can omit any fields and get the default for it. You can omit naming a font for a place="" and get the default font for it.
This is completely replacing theme-specified fonts, for better or for worse. Font shadowing may go back into the theme at some point, instead of in the rc.xml.