Regex Tester & Validator

This regular expression matches a comma followed by exactly three digits (0-9) located at the very end of a line. With the global (`g`) and multiline (`m`) flags enabled, it efficiently scans across multiple lines in a text file to find all occurrences of this pattern. It is particularly useful in subtitle processing or timestamp manipulation, such as extracting or formatting millisecond values or specific color codes at the end of lines.