How much to show, with anything the developer has said on top.

QUNITX_REPL_CONTEXT=10 for ten lines before, 10,2 for ten before and two after, 0 for none at all — a breakpoint you already know your way around does not need a map every time.

import { limits } from './excerpt.ts';

limits().before >= 0; // true — whatever it reads, it is a count of lines