A 2.3 GPA — a C+ average — is the NCAA Division I athletic-eligibility threshold for core academic courses. It's the line between qualifier and non-qualifier status for high school athletes, which is why this specific number gets searched as much as it does despite sitting well below the median high school GPA. For non-athletes, a 2.3 unweighted opens community college and less-selective four-year admission but sits below most state-flagship and merit-aid thresholds.
The NCAA Division I sliding scale starts at 2.3 core GPA. Below 2.3 in your 16 core academic courses, you lose D1 athletic eligibility regardless of SAT/ACT score. Above 2.3, the sliding scale lets you compensate with stronger test scores.