What is graders?

The term "graders" is very broad and lacks a specific technological definition. It generally refers to systems, either automated or manual, used for evaluating or assessing work, performance, or quality. These systems can be found in education (grading student assignments), manufacturing (quality control), agriculture (sorting produce), and many other fields. Without more context, it's impossible to provide a more specific explanation. If you're referring to automated grading systems in education, those systems typically use algorithms and machine learning to evaluate student submissions based on pre-defined criteria.