Funny, they're supporting Firefox, but, pages load soooo slow (multiple platforms, most recent stable browser) that it's hardly worth reading the noise. Even tabbed browsing won't help when the whole browser locks up while trying to render. And, yes, I've tweeked the multi-thread options.
Tribe User Profile Preview - Tribe Browser Policy Explained
Tribe User Profile Previewt: "When we were designing the architecture for our new open profile we took a look at our server logs and made some choices about which browsers we would explicitly support. Currently our stats show: "