Bughouse

It would be great Lichess had bughouse.

Well, crazyhouse is close enough.

look at the url "bughouse 20"

what does that do?

lichess.org/forum/lichess-feedback/bughouse
lichess.org/forum/lichess-feedback/bughouse-2
lichess.org/forum/lichess-feedback/bughouse-3
lichess.org/forum/lichess-feedback/bughouse-4
lichess.org/forum/lichess-feedback/bughouse-5
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.
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Lichess will not add bughouse.

"Because it's a 4-player game, Lichess is designed with 1vs1 game play in mind. You would have to rewrite a lot of the code, maintain it indefinitely and on top of that fragment an already not that big variant community."
lichess.org/forum/lichess-feedback/bughouse-18#4

I know pychess.org (which you can access with your lichess login) has been working on adding bughouse although I'm not sure how close they are to launching it.