backdrop_deliver_html_page in core/includes/common.inc

Packages and sends the result of a page callback to the browser as HTML.

theme_install_page in core/includes/theme.maintenance.inc

Returns HTML for the installation page.

theme_restore_page in core/includes/theme.maintenance.inc

Returns HTML for the restore page.

theme_update_page in core/includes/theme.maintenance.inc

Returns HTML for the update page.

_backdrop_log_error in core/includes/errors.inc

Logs a PHP error or exception and displays an error page in fatal cases.

_batch_progress_page in core/includes/batch.inc

Outputs a batch processing page.