Developer's Guide

to.
Carriers
Hook name
File location
Visible
Description
updateCarrier
AdminCarriers.php
No
Called during a carrier's
update, right after said
update.
Creating a PrestaShop module
Modules' operating principles
Modules are the ideal way to let your talent and imagination as a
developer express themselves, as the creative possibilities are many.
They can display a variety of content (blocks, text, etc.), perform many
tasks (batch update, import, export, etc.), interface with other tools...
Modules can be made as configurable as necessary; the more configurable
it is, the easier it will be to use, and thus will be able to address the need
of a wider range of users.
One of the main interest of a module is to add functionalities to
PrestaShop without having to edit its core files, this making it easier to
perform an update without having the transpose all core changes.
That is way you should always strive to stay away from core files when
building a module, even though this can prove hard to do in some
situations...