I'm creating an extremely difficult challenge requiring advanced regex techniques. This challenge mixes various complex patterns: emails with special characters and brackets, international phone numbers with extensions and variable spacing, dates in multiple formats (with slashes, hyphens, and dots), a symmetric license plate pattern that could tempt one to use backreferences, both IPv4 and an IPv6 address, a MAC address, an email using a literal IP inside square brackets, and an ISO 8601 dateti... (truncated)