Accessibility
DateRangeInput is one group. label names it. rangeLabels name the start and the end and are read before the group label. The trigger is a read-only text field with the formatted range (or the active mode's formatted end); it opens the calendar popover. Dates are chosen on the calendar, not typed in the trigger.
The calendar button uses calendarLabel. The popover uses calendarTitle, which is not painted. With confirm, Apply, Reset and Clear use applyLabel, resetLabel, and clearLabel when Before, After and Between are offered. Apply is the only primary action; Reset and Clear are secondary, not destructive.
Confirm footer. Day presses only change a draft until Apply commits. Reset restores the value held when the popover opened and stays open. Clear empties the draft and stays open. Escape and an outside press close without committing.