First, some background about the concept itself. In bread baking, “desired dough temperature” (DDT for short and sometimes called “final dough temperature”) is an important idea. If you’re following a recipe that says the dough should be 78°F (26°C) after mixing but you instead start with 70°F (21°C) dough, all of the fermentation times in the recipe are going to be off by a wide margin and you might end up underproofing and ruining the bread.
To understand why this is, take a look at this graph which shows how sourdough yeast activity changes based on temperature: