On the surface, I think you're describing fire-fighters (who are loved for solving high-visibility problems), but in retrospect, I think these are also developers with very high reading comprehension and reasoning abilities. That may not make them great designers and architects (though some are), but they can see code for what it is and fix it, as in "The Big Lebowski", "in the parlance of our times" (in other words, in a way that fits the code as it was originally written).