Build, test, and debug regular expressions
Matches US-style phone numbers preceded by a 'Phone:' label, accepting formats like (555) 123-4567, 555-123-4567, or 5551234567. The area code, prefix, and line number are each captured in separate groups, with optional parentheses, whitespace, hyphens, and trailing newline. The global flag enables finding all occurrences in text, making it useful for extracting contact info from forms, logs, or scraped documents.