A google search for "most obscure computer language" (with "computer language" being the terminology they use in the episode) returns this article as the first

A google search for "most obscure computer language" (with "computer language" being the terminology they use in the episode) returns this article as the first result https://blog.payara.fish/6-of-the-weirdest-most-obscure-programming-languages https://blog.payara.fish/6-of-the-weirdest-most-obscure-prog... My guess is that they just skimmed through that and picked "Malbolge" because it sounds the best.