Earlier quoted context omitted.
Isn't it supposed to be fubar? fucked up beyond any recognition?
Yes that’s the original spelling & meaning. But using the spellings foobar, foo, bar, and sometimes baz, have been used for decades in programming as examples, temporary names, stand-ins etc. I just assumed that spelling it foo was meant to distance it from the curse word slightly while simultaneously making the pronunciation more clear (i.e. foo not fuh); foo just makes a good nonsense word.
They are called metasyntactic variables and there’s a handful of them for English, but also standard ones in other language.