[thelist] Mozilla: Use Stylesheet?

[Judah McAuley]

In Mozilla (currently using 0.9.8), there is a menu option under View
that says Use Stylesheet.  When I expand it's menu, it only lists a
single option: none and that option is choosen.  I assume that this is
an accessibility feature, but searching the docs on mozilla.org does not
tell me how to use a different stylesheet.  I'm assuming that I would
have to drop it somewhere or register it.

Can a user specify a stylesheet that is not listed in the HTML document?
  And if so, how?

TIA,
Judah