[orca-list] What is Enable assistive technologies checkbox for?

[Rastislav Kiss <rastislav kish gmail com>]

Hi everyone,
here I am, with another mistery.
I thought, that just like on Windows, all that's needed to do in order
to use computer with screenreader is to turn it on.
Therefore I was quite surprised, when I found Assistive technologies
settings, and a checkbox "Enable accessibility technologies" in
unchecked state.
Does someone know, what is this checkbox for?
I don't need any assistive technologies except screenreader, so I would
like my system to stay as normal as possible, thus I didn't try to
check this option before asking.
On the other hand, I noticed that some frameworks with accessibility
bridges, namely Java and Mono are unaccessible, so I wonder, are there
global variables, which would make these things work?
Or may be it is just coincidence, but then I'd be curious, what is the
checkbox for.

Thanks!

Best regards

Rastislav