2011/5/2 Toledo, Luis Carlos <lscrlstld@gmail.com>

> 'L' stands for "last". When used in the day-of-week field, it allows you to specify constructs such as "the last Friday" of a given month. In the day-of-month field, it specifies the last day of the month.
>
> Retirado do manual do cron

Estranho, não achei isso no man do cron padrão do CentOS (vixie-cron).