The #Mozilla rebranding announcement says that the "green palette that is quintessential with nature and nonprofits that make it their mission to better the world, this is a nod to making the internet a better place for all."
I'm not sure the enviro movement is the first thing I think of when I see green text on black, with a blinking green text caret.
https://blog.mozilla.org/en/mozilla/mozilla-brand-next-era-of-tech/