I'm not an security expert, so I have asked in our internal browser channel, but as far as I know I can say, that spectre attacks are based on very specific and advance computer behavior, but other than they're not any different from any other attacks or viruses. I also believe, that all flags data are set to the best settings at all, compromising security and pages functionality (you can of course disable everything for best security, but then you may not load a single page). In case I receive any update, I will let you know.
I hope I have helped.
Avast Secure Browser Tester, Adam H
