user_custom_theme in core/modules/user/user.module

Implements hook_custom_theme().

user_menu_site_status_alter in core/modules/user/user.module

Implements hook_menu_site_status_alter().

user_menu_title in core/modules/user/user.module

Menu item title callback for the 'user' path.

user_pass_page in core/modules/user/user.pages.inc

Menu callback for reset password form.

user_preprocess_page in core/modules/user/user.module

Implements hook_preprocess_page().

user_preprocess_page_components in core/modules/user/user.module

Implements hook_preprocess_page_component().