Racket is now on Instagram at <https://www.instagram.com/racketlang/>
Racket has a presence on many social media platforms due to the diversity of the people who use Racket. Look here to find one that suits you: https://racket.discourse.group/t/racket-on-social-media-help-others-find-out-about-racket/1927
It is a joke. In the anime Firefighters they use it in a made-up religion substitute for “amen” (and they put hands in a certain way resembling the fire).
Admittedly not the smartest thing I wrote today. Either way, for the reference: https://www.youtube.com/watch?v=wpWd40Gg1t8