Function format_interval_array 

pub fn format_interval_array(items: &[Option<IntervalSpan>]) -> String

v7.37.5 β-P4 — render an INTERVAL[] in PG’s external array form. Each non-NULL element is double-quoted because interval text contains spaces (1 day) and colons (24:00:00) that would confuse the comma-separated parse: {"1 day","24:00:00",NULL}. Inner " doesn’t occur in interval text so no escaping is needed; backslashes likewise can’t appear.