Files in these folders are autoloaded:
includes/extra_datafiles/ includes/languages/english/extra_definitions/ includes/functions/extra_functions/ includes/extra_configures/ admin/includes/extra_datafiles/ admin/includes/languages/english/extra_definitions/ admin/includes/functions/extra_functions/ admin/includes/extra_configures/
Note that the folder
/extras at the root of Zen Cart is
a set of utilities, not autoloads.
Autoloads are designed to make upgrades easier since using them means fewer core file edits.
The usage of these folders is as follows:
includes/extra_datafiles: definitions of table names and PHP files which have been added. Using this folder means not having to update the core files
includes/languages/english/extra_definitions: language constants which have been added. Using this folder means not having to update the core files
includes/functions/extra_functions- global functions which have been added. Using this folder means not having to update
includes/extra_configures- global configuration settings which have been added. Using this folder means not having to modify
The admin folders use the same pattern.