@rwhitese,
From what I can tell, the extension is supposed to install along with the downloaded application software. However, it does not seem to have done so in Brave. You can install the same extension by way of the Chrome web store, however:
That said, while I did manage to install the extension correctly and the square does appear, it doesn’t seem to be active when browsing. I’ve reached out to some team mates for additional eyes on the issue.