Regex Tester & Validator

This PCRE regex is designed to parse log entries from an Email Security Appliance (ESA), specifically targeting lines containing "ESAAttachmentDetails". It captures attachment filenames within single quotes that do not end with the extensions "eml", "p7s", or "xml", occurring before the "ESAFriendlyFrom" field. It is highly useful for filtering email logs to identify attachments of interest while ignoring common system or signature files.