And thanks to nobody for help on this one ...
That's okay, though, as it took a bit of finagling until I got Tor Browser working more or less right. I just don't remember it being so much work, but then I haven't used it for quite a few years.
In the end, I went back to the version that's current for my system, although I don't know if that was part of the cure, as I haven't tried using the sid (or unstable experimental version, or whatever it is). I thought it might be something to do with Debian and Devuan not playing well together, but the packages are in the Devuan repositories, so I don't think that was it.
Anyway, I am posting my results here, just it case somebody else out there might find it useful, if they are trying to install it.
As I mentioned before, for my own system, I had to run the command "firejail torbrowser-launcher"; but that's because I have firejail installed, so I have to do it with all my browsers, as well as a few other programs. If you don't use firejail, then you can ignore that bit.
Once I finally got it to launch: when I tried to configure torbrowser to use proxy servers, but it would only accept the http/https configuration, 127.0.0.1:8118, which is to use privoxy. Somewhere, I believe on the Tor Project website, I read that Socks5 is the preferred configuration: 127.0.0.1:9050, and set that to be used by all protocols. But when I tried this, I couldn't connect.
Somewhere or other I got the notion to try enabling the built-in bridges in the Tor Browser. I tried 'em all, off and on, the obs4, snowflake and meek, and all seem to work, but takes time, and requires patience. Eventually, using bridges, the Tor Browser connnected, and only then could I use the Socks5 configuration.
Since I started doing this, my internet connection also seems much more stable, though this may be a coincidence, or not.
This brings me to the point that connects it to TDE, so that this is not completely off-topic.
This issue, which concerns tork-trinity, is what started all this bother. I would like to be able to continue to use tork-trinity to manage my proxy connections, as it has many features that I will miss if I try doing it manually. For one thing, I can watch all my internet traffic over proxies in real time. (And since I started using the Tor Browser, I now also see the new connections, bridges, and so on. It may be, because I use the bridges, and there always seems to be a trickle of bits/second, that it keeps my connection alive?)
The problem with tork-trinity is that it's a kind of legacy package, I would guess. The KDE3 version was discarded when KDE started on its terrible campaign of transmogrification into an ugly pile of krap, and only Trinity desktop keeps it alive. However, I cannot add the most recent Tor bridges to tork-trinity. It seems that tork-trinity uses a list that is obsolete, and now they are listed in a different form.
Is there some way, for the present moment, to copy those Tor bridges, that I get from the Tor Browser, and paste them into tork-trinity?
tork-trinity > Settings > Configure TorK > Firewall/Censor Evasion > Evade Censorship
When I click the button to use bridges My State or Service Provider Censors the Use of Tor I end up with a lot of useless bridge addresses, and it sometimes interferes a little with my connection, or so it seems.
If there is no way to hack it to use the current bridges, then is it possible to modify or upgrade the tork-trinity package, so that it is up-to-date with current usage methods for the Tor bridges? I don't know how much trouble this might cause, and I realize that the developers don't have time for everything.
But tork-trinity is so very useful. I feel sure others would agree, if they have used it.
If necessary, I can make a feature request, or whatever is appropriate.
Bill