I'm creating an extraordinarily difficult challenge that combines:
1. Nested XML-like tags with balanced quotes and special characters
2. Complex mathematical expressions with subscripts/superscripts requiring precise matching
3. Internationalized domain names with punycode and Unicode
4. JWT tokens with specific internal structure
5. Tricky date-time formats with timezone offsets
6. Version numbers with build metadata
7. Special escape sequences that must be matched exactly
8. Similar but non-m... (truncated)