backdrop_requirements_url in core/includes/install.inc

Returns a URL for proceeding to the next page after a requirements problem.

drupal_current_script_url in core/includes/drupal.inc

Returns the URL of the current script, with modified query parameters.

install_select_language in core/includes/install.core.inc

Installation task; select which language to use.

install_select_language_form in core/includes/install.core.inc

Form constructor for the language selection form.

restore_info_page in core/restore.php

Provides an overview of the backup restoration process.

restore_progress_page in core/restore.php

Show a progress message while processing a restore.

update_info_page in core/update.php

Provides an overview of the Backdrop site update.