new frame parameters

[Drew Adams]

I see some new frame parameters in Emacs 23 (new wrt 22), and I don't see them
documented anywhere. I also don't see what effect they have. 

For example, I see (horizontal-scroll-bars . t). What is it for? It doesn't seem
to have any effect, at least on Windows - I don't see a horizontal scroll bar.

These are the new frame parameters I see in my setup. I don't find any of them
documented in the Elisp manual.

buried-buffer-list
environment
explicit-name
font-backend
font-parameter (not `font')
horizontal-scroll-bars
reverse
window-system
parent-id