...Once you hit an error you'll be presented with an interactive tree representing your stacktrace which you can explore. To turn interactive errors off and return to using normal stack traces call toggle(). Call toggle() again to turn it back on. Press up and down arrows to move through the stacktrace. Press space to fold or unfold the currently selected line. A + will appear on folded lines. Press enter once finished. If you are on a line that references a particular file then that will present additional options in the next menu. q can be pressed to exit back to the REPL.