Weird. I don’t see that feature yet on Firefox add-on.
Can’t see it either on Chromium browser (Linux).
They have said it will come first to the Firefox addon.
Well, maybe I am blind or it might take another couple of days.
Github shows latest stable version as 8.0.10 …
My current version is 8.0.10 …
This version is 22 days old, and does not include the Swap feature. Looking forward to the next stable release for Chromium/Brave Browser.