A "hot broiler" refers to an oven's setting that uses intense heat from above to cook food quickly, often giving it a browned or crispy exterior. Full definition
Meanwhile, roast your poblano peppers: Place peppers on a baking sheet and place under hot broiler until very black, turning once to ensure the entire pepper is blistered and blackened. (thewickednoodle.com)
Roast the tomato on a baking sheet 4 inches below a very hot broiler until blackened, about 25 minutes, then flip it and roast the other side; cook, then peel, collecting all the juices with the tomato. (ciaprochef.com)
Roast the tomatillos, chile (s) and garlic on a rimmed baking sheet 4 inches below a very hot broiler, until blotchy black and softening (they'll be turning from lime green to olive), about 5 minutes. (mixedgreensblog.com)