It's chaining functions with a dot, just like you do in typical OO languages.
When it's OO, it's a virtue that everyone loves - a "fluent interface".
When it's FP - oh it's unreadable! Why don't they just break every line out with an intermediate variable so I know what's going on!
Could you elaborate? AFAIK tacit programming tend to be scrambling around composition, paren, and args which makes left-to-right reading significantly harder for function with arity greater than 2.
I find Java's method reference or Rust's namespace resolution + function as an argument much better than Haskell tacit-style for left-to-right reading.