firefox
"Vivaldi browser is part open-source, part closed-source" They can make it sound great, but in the end its not. https://vivaldi.com/blog/vivaldi-browser-open-source/
JWST Uses Javascript 
www.theverge.com The James Webb Space Telescope runs JavaScript, apparently
It actually seems like a clever system.
just look at it
firefox
opera also used to maintain their own browser engine if i remembered correctly, but they all just dipped
siriusmart @feddit.uk
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