This DisplayString reports the captured sub-match text from the most recent regular-expression match for this fscan table entry, i.e., any parenthesized capture groups within the pattern. An admin uses it to extract specific details from a matched log line, such as a hostname or error code embedded in the matched text, without having to parse the full log line separately. For example, a pattern designed to capture a failed username in a login-failure line would expose that captured username here for the admin to review.