Lua has its own native pattern syntax in the string library, but sometimes a real regex engine is more useful. Wireshark comes with Perl Compatible Regular Expressions version 2 (PCRE2). This engine is exposed into Wireshark’s Lua engine through the well-known Lrexlib library. The module is loaded in the global environment using the "rex_pcre2" table. The manual is available at https://rrthomas.github.io/lrexlib/manual.html.