Ah yes, thank you for the reminder!
Now that I actually have a career and money I have no problem giving back. I'm glad I can donate to Ubuntu and Wikipedia nowadays. I am grateful for everything Firefox has given me for well over 10 years...
I really don't know what XUL is (intermediate language between HTML and FF UI?), but I guess I do feel sorry for people who have been using Thunderbird. I hope it's significant enough a property that people will want to continue, write it in Rust?