Yea, not sure 'what' virus scanner is used. I'll have to look into that some more.
Found it.
Quote:
Anti-Virus Software
Firefox 3 integrates elegantly with your antivirus software. When you download a file, your computer’s antivirus program automatically checks it to protect you against viruses and other malware, which could otherwise attack your computer. [available in Windows only]
Firefox web browser | Security & Privacy |