Bukkit

Full descriptions can be found in the respective file headers.

config.yml

This file mainly contains information concerning each world as well as general options such as the reference tick, SQL database usage, placeholder activation, etc.

lang.yml

This file contains the different translations. It is possible to modify them and add new languages. It is also possible to activate automatic translation depending on each player's locale.

cmds.yml

This file allows you to schedule the execution of commands at specific times and dates, with the possibility of repeating them according to the chosen cycle.
The reference time and date can be that of any world, or the actual time.