atched. This can refer to grouping variables, variables from the
environment and {.included} and {.matched} or {.missing} (included =
matched+missing), {.count} and {.total} - group and overall counts
respectively, e.g. "excluding {.matched} items and {.missing} with
missing values".</p></dd>


<dt id="arg--headline">.headline<a class="anchor" aria-label="anchor" href="#arg--headline"></a></dt>
<dd><p>a glue specification which can refer to grouping variables
of .data, or any variables defined in the callin