hook_hook_info()
Defines one or more hooks that are exposed by a module.
Normally hooks do not need to be explicitly defined. However, by declaring a hook explicitly, a module may define a "group" for it. Modules that implement a hook may then place their implementation in either $module.module or in $module.$group.inc. If the hook is located in $module.$group.inc, then that file will be automatically loaded when needed. In general, hooks that are rarely invoked and/or are very large should be