You know those game-worn jersey trading cards, with a swatch of cloth cut from a player's uniform? They have those for pro wrestling too. Usually not sweaty spandex, thankfully. Like this 2001 Chris Jericho "event-worn t-shit" insert, with a couple square inches taken from precisely the wrong spot on this wall of text.
It's just an accident, as the vivisection of a jersey or shirt is more or less random. And maybe not that unfortunate at that: the Jericho "gay" card sold on eBay for 100 bucks, five times the usual going rate.