date_format_type_options in core/modules/date/date.module
Creates an array of date format types for use as an options list.
system_date_format_delete in core/modules/system/system.module
Deletes a date format from the database.
system_date_format_load in core/modules/system/system.module
Menu loader function for a date format.
system_date_time_formats in core/modules/system/system.admin.inc
Displays the date format strings overview page.
system_get_date_types in core/includes/drupal.inc
Alters Backdrop's list of defined date formats and attributes to return the expected date types and attributes for Drupal's system_get_date_types() function.
system_tokens in core/modules/system/system.tokens.inc
Implements hook_tokens().
system_token_info in core/modules/system/system.tokens.inc
Implements hook_token_info().
views_handler_field_date::options_form in core/modules/views/handlers/views_handler_field_date.inc
Default options form that provides the label widget that all fields should have.
_date_field_widget_settings_form in core/modules/date/date.admin.inc
Helper function for date_field_widget_settings_form().