Has anyone tried the Avira Browser Protection Plug-In for Firefox. It appears tom plug the hole left by using NS with FF 41 and it's a free extension.
"1. Safe Browsing
Never land on a harmful website.
2. Avira Price Comparison
Never overpay when shopping online.
3. Privacy Protection
Don't allow networks to track you.
4. PUA Shield
Identifies hidden programs in download portals and recommends secure alternatives.
Poisoned links and phishing webpages are blocked - so you'll know every website you visit is safe!
Keep your navigation private
Blocks browser trackers, which prevents thousands of ad networks from monitoring what you search and shop for.
Block Potentially Unwanted Applications
Notifies you when clicking on software that contains a potentially unwanted application, and offers you your desired software from a secure website.
Always get the best deals
Saves you money by finding the best deal for whatever product you're shopping for. All deals listed are from safe websites!"
https://www.avira.com/en/avira-browser-safety