(TenFourFox maintainer) Thanks, glad it was helpful to you. There is some TenFourFox code in this respin which is being used to support the widget code, and there is work in progress to forward-port its JIT. I'm not writing that code but I am advising on it as questions come up.

Thank you for your work on it! I love that I can browse most of the modern web on G4 and G5 Macs still.