Ok, here is a strange one. I installed Firefox to my systems at home around version 25 and have been updating them ever since. It was my understanding that Firefox added a feature that scans all downloads for malware etc.
Installed Firefox clean to a clean build today and when downloading files like dopdf7 to add to this clean build for pdf creation etc, I noticed that Firefox was not scanning the downloads.
I never installed any special addon for this download scanner ( browser antivirus feature ) on home systems. So did Firefox once make this a default feature around version 25 and then removed it from being a default feature with latest Firefox version.
All info on google doesnt clear this question up, although I do see that there are addons that can be added to add an antivirus to the browser.
When i get home from work I am going to check out my home systems to try to figure out what feature is turned on or addon added that I never added on my own to see if I can add that feature enabled to this clean build I worked on today.
I like how my home systems scan all downloads with firefox before being able to launch executables etc.