com/templates/repo/issue/search.tmpl

<form class="ui form ignore-dirty">
	<div class="ui fluid action input">
		<input type="hidden" name="type" value="{{$.ViewType}}"/>
		<input type="hidden" name="state" value="{{$.State}}"/>
		<input type="hidden" name="labels" value="{{.SelectLabels}}"/>
		<input type="hidden" name="milestone" value="{{$.MilestoneID}}"/>
		<input type="hidden" name="assignee" value="{{$.AssigneeID}}"/>
		<div class="ui search action input">
			<input name="q" value="{{.Keyword}}" placeholder="{{.i18n.Tr "explore.search"}}..." autofocus>
		</div>
		<button class="ui blue button" type="submit">{{.i18n.Tr "explore.search"}}</button>
	</div>
</form>