And he’ll be wearing it on the outside
A Look Inside Superman Red Trunks in Today's Action Comics #1000 (Semi-SPOILERS)
Superman will find his red underwear in Action Comics #1000 - Polygon
Action Comics celebrates issue #1000 with red trunks
Superman hoping to make red trunks cool again, getting old look back in Action Comics No. 1000
Superman's Red Trunks Return in Action Comics #1000 - IGN
Superman hoping to make red trunks cool again, getting old look back in Action Comics No. 1000
DC comics' Tom King & Brian Bendis: Batman, Superman, and the industry - Polygon
A Look Inside Superman Red Trunks in Today's Action Comics #1000 (Semi-SPOILERS)
Do Superman's red underwear serve any purpose other than being aesthetically pleasing or for comfort reasons? - Quora