Test, validate and match regular expressions
Validates Content Security Policy (CSP) source lists, supporting keywords like 'none', 'self', 'sameorigin', 'deny', as well as URI patterns with optional scheme, host, and port components. Accepts single sources or space-separated lists of sources (e.g., https://example.com:443 http: 'self'). Uses named groups to identify individual components like scheme, host, port, and separators. Commonly used for validating CSP directive values in security headers or configuration files.