Build, test, and debug regular expressions
Matches European-style timestamps in DD.MM.YYYYTHH:MM:SS.ff format, e.g., 31.12.2023T23:59:59.99. It captures the day (00-31), month (01-12), a 4-digit year, and a 24-hour time with minutes, seconds, and hundredths of a second. Useful for parsing log files or validating datetime strings. Note a subtle flaw: month 10 (October) is not matched due to how the month alternation is written.