Norton detected a Threat Rated 1 out of 5 stars
After the most recent update, Norton detected a threat from this extension. I will not be using this anymore.This review is for a previous version of the add-on (0.3.0).
This is definitely a false alarm
The add-on's complete source code is out there and you can see for yourself whether there is anything malicious.
You should report this to Norton instead of complaining it here.
FYI: here's the result from virscan.org.