The checks

Every check Wsec runs, with the reason it exists. A failed check costs points by severity: critical 30, high 15, medium 8, low 3. A warning costs half. Notes and checks that could not run cost nothing.

The grade follows the score (A from 90, B from 80, C from 65, D from 50), but any failed critical check caps it at F and any failed high check caps it at C, because one open door matters more than many small gaps.