Tested twice, in FF 67.0.0 Webroot Extension gives green check mark. Upgrade FF to 68.0, no longer get green check marks. Did restores and tested twice, same results. Also un-installed and re- installed Webroot. No differences.
For some reason it is now working and I haven't changed a thing, earlier Webroot wasn't showing up as an Addon Extension or Plugin under FF, it had just disappeared. It was there on 67.0.4 Then about 10 minutes later I checked and it was under Addon but was disabled??? Strange how it wasn't there and then was! Anyway I enabled and it's working.