For maintainability, security and reliability ratings it is not obvious why the rating is A, B, C, D or E. To help users to understand we should add an explanation tooltip saying:
- Maintainability Rating is B, because the technical debt ratio is greater then 0.1%
- Security/Reliability Rating is C, because there is at least one critical vulnerability/bug.
The thresholds for maintainability rating are stored in the sonar.technicalDebt.ratingGrid property. The thresholds for security and reliability ratings are hardcoded.