View source for Past Events/Year number

<div id="years" class="d-flex flex-wrap event-filter-group mega"><!--

--><span class="clear-filter float-right" style="display:none"></span><!--

--><h4 class="collapsed moha-button" data-toggle="collapse" data-target="#event-filter-year" aria-expanded="false">Year</h4>
<div id="event-filter-year" class="pb-4 collapse event-filters">{{#arraydefine: years|{{#ask: [[Category:Events]]|?Year number# |mainlabel=- |headers=hide |format=array |sep=; |manysep=; |limit=5000 |searchlabel=}}|;|unique, sort=asc}}<!--

-->{{#arrayprint: years
  |
  |@@@
  |{{#widget: input|type=checkbox|name=year|value=@@@|class=d-inline-block m-1}}
}}</div>
</div>