According to My Wot, at least the domain, not necessarily the add-on, but possibly both, have a virus or malware. The nc.ddns extensions site has a broken link, but the Better Privacy add-on works fine. If this add on is unsafe to use, please advise me and I’ll uninstall it:
Although the link is currently broken, it looks like sources (WOT, Webutation, Virus Total, etc) vary considerably on the same links per product, in this case Better Privacy, which can make it very difficult to know who to go by when results differ, but it’s very reassuring that you’ve used this software long term without problems and that Virus Total gives it a positive outcome, so I’ll go by your recommendation .
I will continue to use Better Privacy, as well as Disconnect, Ghostery and Do Not Track Me among other add-ons and reinstall them when I buy my next computer. I don’t know how extensively Firefox add-ons reduce the speed of navigation, but the above are some of the most essential add-ons for privacy and others for their respective purposes.