What is a firefighter jacket and why has it suddenly become fashionable?

Firefighter jackets are currently trending. Pictured here is a design by Mfpen. Photo: The New York Times

Many fashion trends are a matter of inches. This one is a matter of cinches.

The firefighter jacket, a variation on the three- or four-pocket chore coat that features weighty metal clasps in place of buttons, has emerged as a curious, clangy spring jacket trend.