7 calls to drupal_maintenance_theme()

authorize.php in core/authorize.php
Administrative script for running authorized file operations.
drupal_flush_all_caches in core/includes/common.inc
Rebuilds the container, flushes all persistent caches, resets all variables, and rebuilds all data structures.
install_begin_request in core/includes/install.core.inc
Begins an installation request, modifying the installation state as needed.
install_display_output in core/includes/install.core.inc
Displays themed installer output and ends the page request.
install_run_tasks in core/includes/install.core.inc
Runs all tasks for the current installation request.
MaintenanceModeSubscriber::onMaintenanceModeRequest in core/lib/Drupal/Core/EventSubscriber/MaintenanceModeSubscriber.php
Returns response when site is in maintenance mode and user is not exempt.
MaintenanceThemeTest::testMaintenanceTheme in core/tests/Drupal/KernelTests/Core/Theme/MaintenanceThemeTest.php
Tests that the maintenance theme initializes the theme and its base themes.

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