- “<widget name="hr_leave_stats"/>” is used in “Time-Off(hr_holidays)” module inside the view having record id=”hr_leave_view_form_manager”
- This widget is extended in “leave_stats_widget.js” file.
- The above Js-file is linked with the template- src-> leave_stats_templates.xml
- If department leaves is available then the template = “t-name="hr_holidays.department_leave"” is called

For Your Reference:
<t t-name="hr_holidays.department_leave">
<table class="o_group o_inner_group table-striped">
<thead>
<tr>
<td colspan="2">
<div class="o_horizontal_separator"><t t-esc="widget.department.data.display_name"/> in <t t- esc="widget.date.format('MMMM')"/></div>
</td>
</tr>
</thead>

and so on .....

- And in t-esc: Month is extracted from date.
- To make changes in Date , you have to inherit the “_setState” method used inside the “leave_stats_widget.js” file.