All right, like anything Tor-related, this requires a bit of patience to get it running properly.
If all you need is to 'fire and forget', sure, follow the instructions *exactly* and you'll get the expected result.
In my case, I've got a tweaked old macOS-based laptop (it's still x64). Because Apple has discontinued this version years ago, I have to run MacPorts to keep everything working nicely. MacPorts currently has a much more recent version of Tor than what Andy offers for download.
In my case — remember, it's Mac! — I decided to install both Tor and its configurations as written by Andy under ~/Applications/torbin
Then, inside this directory, I removed the binary and the dylib, and linked to the ones from MacPorts: that way, if those get updated (they will), there is no fear that it will break anything.
Next comes what Andy calls "the NodeJS native client". This I also put under ~/Applications/torjs — and this is the path to place on the Extension configuration.
Once all that is in place — well, it works. It's slightly more complex to set up than the built-in Tor connectivity of the Brave browser, but, on the other hand, I have a bit more control over what is being launched. It's a good compromise!

Can't you just start tor.exe without all the Node.JS middleware? It's a fair bit of work to install that.

For what it's worth, if you've got the "Windscribe - Free Proxy and Ad Blocker" add-on, you need to disable it. Even when it's been turned off (but not disabled) it stops this add-on from working, for me, it did anyway.👍

🧅

Followed _exactly_the install instructions given and ended up with a full re-install of FF 0.97 to get my browser working again.

did the following:

0. installed this addon

1. Download “Tor Bundle” and extract it in a local directory (https://github.com/andy-portmen/tor-bundle/releases). Put it into ~/.tor-bundle

2. put userdir/.tor-bundle into the options page text box and saved

3. downloaded the native client from https://github.com/andy-portmen/native-client/releases and installed it into ~/.tor-client and then ran ./install.sh script

4. browser console appeared on my gui (fedora 35 + gnome 41) and started spewing massive amounts of errors:

stderr output from native app com.add0n.node: node:events:498
stderr output from native app com.add0n.node: throw er; // Unhandled 'error' event
stderr output from native app com.add0n.node: ^
stderr output from native app com.add0n.node:
stderr output from native app com.add0n.node: Error [ERR_MULTIPLE_CALLBACK]: Callback called multiple times
stderr output from native app com.add0n.node: at new NodeError (node:internal/errors:371:5)
stderr output from native app com.add0n.node: at onwrite (node:internal/streams/writable:431:28)
stderr output from native app com.add0n.node: at node:internal/streams/transform:202:7
stderr output from native app com.add0n.node: at Transform.observe [as handler] (/root/.config/com.add0n.node/host.js:432:5)
stderr output from native app com.add0n.node: at Transform._transform (/root/.config/com.add0n.node/messaging.js:107:8)
stderr output from native app com.add0n.node: at Transform._write (node:internal/streams/transform:184:23)
stderr output from native app com.add0n.node: at writeOrBuffer (node:internal/streams/writable:389:12)
stderr output from native app com.add0n.node: at _write (node:internal/streams/writable:330:10)
stderr output from native app com.add0n.node: at Transform.Writable.write (node:internal/streams/writable:334:10)
stderr output from native app com.add0n.node: at Input.ondata (node:internal/streams/readable:754:22)
stderr output from native app com.add0n.node: Emitted 'error' event on Transform instance at:
stderr output from native app com.add0n.node: at Transform.onerror (node:internal/streams/readable:773:14)
stderr output from native app com.add0n.node: at Transform.emit (node:events:520:28)
stderr output from native app com.add0n.node: at emitErrorNT (node:internal/streams/destroy:157:8)
stderr output from native app com.add0n.node: at emitErrorCloseNT (node:internal/streams/destroy:122:3)
stderr output from native app com.add0n.node: at processTicksAndRejections (node:internal/process/task_queues:83:21) {
stderr output from native app com.add0n.node: code: 'ERR_MULTIPLE_CALLBACK'
stderr output from native app com.add0n.node: }

again and again and again!

5. onion button cannot be switched off / tabs start timing out!

U N I N S T A L L E D

It seems to work fine and it's easy to configure.

You only need to install first this extension and then follow the instructions given by the developer:
1.-Download “Tor Bundle” and extract it in a local directory (https://github.com/andy-portmen/tor-bundle/releases).
2.-Open options page and paste the “root” of the extracted folder in the text box.
3.-Install the native client either from the extension or manually from https://github.com/andy-portmen/native-client/releases
4.-Open the toolbar panel and check Tor integration.

Works just as intended. Yes, the installation is not 'just click continue' with a nice GUI installer, but I guess the addon's target group isn't the typical BDU either.