This is MAUVE++ validator v 3.0.1
MAUVE++(Multiguideline Accessibility and Usability Validation Environment) is a system to evaluate accessibility of websites by checking their HTML and CSS code through guidelines, it provides validation results for different types of stakeholders, and supports validation of W3C WCAG 2.1 guidelines.
Additional information about MAUVE++ can be found in the info & help page and in the following papers:
A more general discussion about the relevance of automatic validation tools in websites' accessibility assessment can be found in the following paper:
Version PNRR 1.4.2