It seems with some JavaScript generated from Java via Gwt. Regardless, I prefer it over VSCode UI.

This can’t be answered in general. Flamegraphs are measurements of what happened. But just like a ruler doesn’t tell you whether a given human is atypically short or tall for its species, a flamegraph can’t tell you which portion of the program takes too long a time. You need to have prior knowledge about data structures, algorithms, memory bandwidth etc in order to confront your justified expectations with the reality and be surprised with something. And it will all depend on the particular program you profile.

No, it doesn’t.

  bool is_even(int n) {
      return true;
  }

  bool test_is_even() {
      return is_even(2);
  }

The number of SML implementations supporting this feature is greater than the number of OCaml implementations. ;)

Obviously in the next step you achieve enlightenment when you then write them as just one horizontal line, but most don’t reach that stage.

Emacs dired works fine on other platforms, which don’t have GNU ls on them, so I’m guessing by default it doesn’t run ls on its own.