7 files declare their use of CalendarHelper in Calendar 8

calendar.module in ./calendar.module

Calendar.php in src/Plugin/views/style/Calendar.php

Calendar.php in src/Plugin/views/row/Calendar.php

calendar.theme.inc in ./calendar.theme.inc

Theme functions for the Calendar module.

CalendarHeader.php in src/Plugin/views/area/CalendarHeader.php

CalendarLegend.php in src/Plugin/Block/CalendarLegend.php

CalendarPager.php in src/Plugin/views/pager/CalendarPager.php