drupal_get_path in includes/common.inc
Returns the path to a system item (module, theme, etc.).
drupal_install_profile in includes/install.inc
Install a profile (i.e. a set of modules) from scratch. The profile must be verified first using drupal_verify_profile().
drupal_load in includes/bootstrap.inc
Includes a file with the provided type and name. This prevents including a theme, engine, module, etc., more than once.
module_list in includes/module.inc
Collect a list of all loaded modules. During the bootstrap, return only vital modules. See bootstrap.inc
system_modules_uninstall_confirm_form in modules/system/system.module
Confirm uninstall of selected modules.
system_theme_data in modules/system/system.module
Collect data about all currently available themes