Update:

I'm smarter than I thought :-)
I did this on the terminal in the folder where I had previously downloaded the extension with git:

git switch master

Previous HEAD position was 5f100b9 pr20
Switched to branch 'master'
Your branch is up to date with 'origin/master'.

git pull

Then I restarted Brave and that seems to have done the trick.

I previously followed instructions on an earlier post to use git to get version 1.8.2.4 into a folder on my computer.

Is there a magic Git incantation I can perform (with the obligatory black candles and pentagram inscribed around me first) which will update me without needing the import/export step?

I'm still learning all this github stuff....