From what I understand, tor browser is running in its own space. It can
only see it's own directory. If you did install torbrowser-launcher
from apt, it's location would likely be (and depending on your
platform and locale):

    $HOME/.local/share/torbrowser/tbb/x86_64/tor-browser_en/Browser/

Everything the browser does is limited to that folder.

It would be likely that your browser is misinstalled and is unable to
interact with your local file system.

torbrowser-launcher is available in beowulf-backport. More info:

    https://packages.debian.org/buster-backports/torbrowser-launcher

On Tue, 19 Jan 2021 07:42:29 -0500
Haines Brown <haines@???> wrote:

> On Tue, Jan 19, 2021 at 12:24:10PM +0100, Ludovic Bellière wrote:
> > And what is the question?
>
> Sorry that I was unclear: I cannot save the data displayed or
> accessed on my browser. For example I have an extension "Save as
> PDF". When I try to save the displayed page as a DPF, whatever
> directory I try to save to returns "Could not read the contents to
> <the directory>". This because Tor Browser it is trying to save to a
> paritition on an unmounted drive. I cannoit save to any other drive
> because it only only sees /dev/sdc partitions.
>
> >
> > On Mon, 18 Jan 2021 16:33:13 -0500
> > Haines Brown <haines@???> wrote:
> >
> > > Whether I install torbrowser-launcher from Beowulf repository or
> > > download it from www.torproject.org, I find that it insists on
> > > saving files to no longer mounted drive.
> > >
> > > When I browse other save locations, all locations are /dev/sdc,
> > > and those locations are not accessible. I cannot write to the
> > > "save files as" field in download preferences. When I set always
> > > ask where to save, I can set the locationin preferences, but I'm
> > > not actually asked where to save it.
> > >
> > > Some time ago /dev/sdc was mounted, but not used for tor browser.
> > > I could not find in what file the tor browser configuration is
> > > located. I have firefox-esp installed, but it does not have the
> > > problem.
>