Finding manufacturer on shingles.

You don't and that's the plan. Even if you determined the manufacturer, they'd deny a claim by simply claiming they weren't installed correctly or just deny they're theirs. And, the only way to even have "a chance" in forcing them to honor their warranty would be a lawyer, lots of money and even more time. Corporations (non-people) mean more than their customers (people) is the moral of the last century's story. A recall is just a super-cheap bailout to silence all of the preyed-upon victim whiners.