Build, test, and debug regular expressions
Case-insensitively matches a word containing 'user' (with optional prefix/suffix text) followed by '=' and captures everything after it. Group 1 grabs the full key term like 'user', 'db_user', or 'search *user', while group 4 captures the assigned value. Useful for extracting username assignments from config files, log lines, query strings, or key-value pairs.