> So my reasoning here is that it's a summary notification, for the dump_summary event, thus I feel quite strongly this is a "summary", it's just a string representation. In fact, given how we've structured these string representation how about #formatted_summary.

Right, the entire notification object is for the `dump_summary` event but it includes many more lines of information than just this.  I think `summary_line` would only make sense if there was only one summary line and this was it (which isn't true; there's also the duration summary line) and `formatted_summary` would only make sense if this returned all of the summary output (it doesn't).

This is only _part_ of the summary so I think it needs to be named to reflect which part.